Technical Drawing—Technical Drawing Terminology (Excerpt from JIS Z 8114:1999)
2026/06/15
[Scope] This standard specifies the definitions of terms used in product technical documentation related to drafting.
1. General Terminology Related to Drafting
| Terminology | Definition | Corresponding English Terms (for reference) |
|---|---|---|
| Technical Drawing | The act of creating a drawing. | drawing, drawing practice |
| Drawing | Technical information represented by diagrams or line drawings in accordance with established rules and, in many cases, drawn to scale. Note : When this term is used as part of a compound word, it is often abbreviated to simply “~-diagram.” | technical drawing |
| figure | An orthographic projection showing the visible parts of an object and, where necessary, its hidden parts. | view |
| drawing | A drawing with information such as dimensions added to the figure. A general term for various types of projections, such as sectional views and perspective views. | view |
| graph | A graphical representation that typically illustrates the relationship between two or more variables within a coordinate system. | chart, graph |
| Tabular diagram | A drawing that presents similar but distinct forms in tabular format. | tabular drawing |
| Calculation chart | A diagram that allows one to determine approximate values for one or more quantities without calculation. | nomograph |
| Specification table | A table included within a drawing to supplement its content. For example, it shows information necessary for machining, measurement, inspection, etc. | tabular |
| Notes (Items) | Information supplementing the content of a drawing, presented as text within the drawing. | note |
| Detail | A graphical representation of an object, a part of an object, or an assembly; it is typically enlarged to provide necessary information. | detail |
| item | A component or assembly of the object shown in the drawing. | item |
| Technical drawing | The act of drafting using drafting instruments such as rulers, compasses, and templates. | instrument drawing |
| CAD drafting | The act of drafting with the aid of a computer. | computer-aided drawing |
| Freehand drafting | The act of drawing by hand without using drafting tools. | Freehand drawing |
| Pencil drawing | The act of drawing using a pencil. | pencil drawing |
| Inking | The act of drafting using drafting pens, ink pens, etc. | inked drawing |
| Composite drafting | The process of creating a new drawing by cutting, pasting, or combining parts of an existing drawing. | composite drawing |
| Specifications | A document that specifies technical requirements for materials, products, tools, equipment, etc. | (technical) specification |
| Bill of Materials | A complete list of parts that make up an assembly (or a subassembly), or a detailed list of parts shown on a single drawing. | item list |
2. Terminology Related to Drawing Formats
| Terminology | Definition | Corresponding English (for reference) |
|---|---|---|
| Drawing Style | A standard, common format for drawings. For example, the shape, size, and placement of the drawing outline, title block, and symbols. | drawing format, layout of drawing sheet |
| (Drawing) border | The margin area provided to prevent damage to the drawing’s content caused by damage to the edges of the drawing. | border, margin of drawing |
| Border line | The boundary line between the drawing area and the outline of the drawing. | frame, borderline |
| Title block | A section provided on a drawing to consolidate information necessary for managing the drawing, such as standard details regarding the drawing’s content. It is used to enter the drawing number, title, company name, and other such information. | title block, title panel |
| Center mark | A mark placed at the center of each side of a drawing to facilitate microfilming or copying. | Centering mark |
| (Drawing) area | A specific area within a drawing. For example, indicated as B-2. | division, zone |
| Division symbol | A symbol used to indicate a zone on a drawing. Note: Division symbols are based on the grid reference system specified in JIS Z 8311. | grid reference symbol, zoning symbol |
| Cutting marks | A mark placed on the original drawing for convenience when trimming copies. | trimming mark, cutting mark |
| Parts table | A section provided on a drawing to record details (such as part names, materials, and quantities) of the object shown on the drawing or its constituent parts (components). | item block, block for item list |
| Reference number | A number used to match the parts shown on the drawing with those listed in the item block or parts list. | reference number |
| Revision history section | A field provided to record the history of changes to the drawing. | Revision block |
| Scale bar | A scale provided to indicate the degree of reduction or enlargement when a drawing is scaled. | metric reference graduation, comparative graduation |
3. Technical Drawing Terminology
3.1 Terminology Related to Scales
| Terminology | Definition | Corresponding English (for reference) |
|---|---|---|
| Scale | The ratio of the size (length) of a figure to the size (length) of an object. | scale |
| Actual scale | The scale used when drawing a figure to be the same size (length) as the object. Note: Also called actual size. | full scale, full size |
| enlarged scale | A scale used when drawing a figure that is larger (in length) than the actual object. | enlargement scale, enlarged scale |
| Reduction scale | A scale used when drawing a figure at a size (length) smaller than the size (length) of the object. | reduction scale, contraction scale |
3.2 Terminology Related to Lines
| Terminology | Definition | Corresponding English (for reference) |
|---|---|---|
| Solid line | A continuous line. | continuous line |
| Dotted line | A line consisting of short line segments repeated at regular intervals. | dashed line |
| Skipped dashed line | A line consisting of segments where the length of the line and the spacing between them are equal. | dashed spaced line |
| Dotted line | A line consisting of very short segments arranged at slight intervals. | dotted line |
| Dotted-dash line | A line consisting of alternating elements of two different lengths: long and very short (dashes). | long dashed and short dashed line |
| double-dotted line | A line in which elements of two different lengths—long and very short (dash)—are repeated in the order long, very short, very short. | long dashed double-short dashed line |
| Single-short dashed line | A line consisting of two types of line elements—short and very short (dots)—repeated in sequence. | dashed dotted line |
| Two-point short dashed line | A line in which line elements of two lengths—short and very short (dots)—are repeated in the order of short, very short, and very short. | dashed double-dotted line |
| Triple-dotted line | A line in which two types of line elements—short and very short (dots)—are repeated in the order of short, very short, very short, and very short. | dashed triple-dotted line |
| Single-dot long dash | A line consisting of two types of line elements—long and very short (dot)—repeated in the order long, very short. | long dashed dotted line |
| Two-point long dotted line | A line consisting of two types of line elements—long and very short (dots)—repeated in the order of long, very short, and very short. | long dashed double-dotted line |
| Triple-dotted line | A line consisting of two types of line elements—long and very short (dot)—repeated in the order long, very short, very short, very short. | long dashed triple-dotted line |
| Single-dot double-dash line | A line consisting of two types of line elements—short and very short (dot)—repeated in the order short, short, very short. | double-dashed dotted line |
| Two-dot, two-short line | A line in which two types of line elements—short and very short (dots)—are repeated in the order short, short, very short, very short. | double-dashed double-dotted line |
| Triple-dotted double-dashed line | A line in which two types of line elements—short and very short (dots)—are repeated in the order short, short, very short, very short, very short. | double-dashed triple-dotted line |
| Zigzag line | A line combining straight lines and zigzag shapes. | Continuous narrow line with zigzags |
| Thin line | A relatively thin line among the lines that make up a shape, diagram, or drawing. | narrow line |
| Thick line | A line that is relatively thick among the lines that make up a figure, diagram, or drawing. Note: It should be twice as thick as a thin line. | Wide line |
| Extra-thick line | A line within a figure, diagram, or drawing that is drawn particularly thick for a specific purpose. Note: It should be twice as thick as a thick line. | Extra wide line |
| Outline | A line that represents the shape of the visible parts of an object. | visible outline |
| hidden line | A line representing the shape of the invisible parts of an object. | hidden outline |
| Center line | A line indicating the center. | centre line ★ "centre" is British English |
| axis of symmetry | A line representing the axis of symmetry of a symmetrical figure. | line of symmetry |
| Pitch line | A line used to determine the pitch of a repeating pattern. | pitch line |
| center of gravity line | A line connecting the centers of gravity of cross-sections perpendicular to the axis. | centroidal line |
| Break line | A line representing the boundary when a portion of an object is temporarily removed. | line of limit of partial or interrupted view and section |
| Cutting line | A line indicating the cutting position on the corresponding drawing when drawing a cross-sectional view. | line of cutting plane |
| Rotated section line | A line representing a cross-section of a part within a figure rotated by 90°. | outline of revolved sections in place |
| Imaginary lines | a) A line representing the position of adjacent parts or tools, jigs, etc. b) A line representing a moving part at a specific position during movement or at the limit of its movement. | fictitious outline, imaginary line |
| Original outline | A line drawn on a drawing to represent the shape of the object before machining. | initial outline |
| Contour line | In topographic projection, the points of intersection of horizontal planes at predetermined heights above or below a reference horizontal plane, used to represent the surface. Note: Contour lines are drawn in appropriate units of measurement, and contour levels may be single or multiple. | level contour line |
| Special designation line | A line representing an area where special requirements, such as sections requiring special processing, are specified. | line for special requirement |
| Dimension line | A line drawn parallel to the direction of measurement (length or angle) to indicate the dimensions of an object. | dimension line |
| Dimension leader line | A line extending from a shape to indicate a dimension. | projection lines |
| extension lines | Lines drawn to indicate descriptions, symbols, etc. | leader line |
| Reference line | A line that indicates a point of reference, particularly for determining position. | reference line, datum line |
| Benchmark line | A line representing the position of the water surface or liquid surface. | line of water level |
3.3 Terminology Related to Projection Methods
| Terminology | Definition | Corresponding English (for reference) |
|---|---|---|
| Projection Method | Rules used to convert three-dimensional objects into two-dimensional images. This assumes the use of a central projection or a plane projection. | projection method |
| Coordinate system | A basis for defining the relationship between points in space and their corresponding three coordinates. The reverse is also true. Note: This term is often used to refer to Cartesian coordinates. | coordinate system |
| Coordinates | In a coordinate system, a combination of specified numerical values (in units of corresponding magnitude) that uniquely determines the position of each point. Note: This term is often used to refer to Cartesian coordinates. | coordinates |
| coordinate axes | Three reference lines in space that intersect at the origin. These form a coordinate system. Note: This term is often used to refer to Cartesian coordinate axes. | coordinate axes |
| horizontal axis | A coordinate axis used as a reference for indicating the horizontal plane. | horizon |
| coordinate plane | Each of the three planes defined by any two coordinate axes. Note: This term is often used to refer to a Cartesian coordinate plane. | coordinate plane |
| Projection plane | A plane onto which an object is projected in order to obtain an image of the object. | projection plane |
| horizontal plane | A horizontal plane passing through the center of projection. | horizon plane |
| Cartesian coordinate system | A coordinate system based on the relationship between three mutually perpendicular axes (coordinate axes) originating from the same point (the origin) and the units of measurement used to express their lengths. | rectangular coordinate system |
| Rectangular coordinates | In the rectangular coordinate system, the distance from a point in space with given three rectangular coordinates to the coordinate plane. Note: Usually referred to simply as "coordinates." | rectangular coordinates |
| Orthogonal coordinate axes | Coordinate axes that intersect at right angles. Note: Usually referred to simply as "coordinate axes." | rectangular coordinate axes |
| rectangular coordinate plane | Coordinate planes that intersect at right angles. Note: Usually referred to simply as "coordinate planes." | rectangular coordinate planes |
| Cylindrical coordinate system | A coordinate system based on the horizontal coordinate axis, its origin, and the units of measurement. | cylindrical coordinate system |
| Cylindrical coordinates | Refers to the following three coordinates of a point in space in the cylindrical coordinate system: radius (the distance from the vertical axis passing through the origin to the point), azimuth (the angle between the vertical plane containing the point and the origin and the horizontal axis), and height (the distance from the horizontal plane containing the origin to the point). | cylindrical coordinates |
| cylindrical coordinate axes | A horizontal line and its origin. | - |
| Polar coordinate system | A coordinate system based on a reference system using polar coordinate axes and their units of measurement. | polar coordinate system |
| Polar coordinates | Refers to the following three coordinates of a point in space in the polar coordinate system: radius (distance between the point and the pole); azimuth (angle between the vertical plane containing the point and the origin and the polar coordinate axis); and polar angle (angle between the horizontal plane containing the point and the line connecting the point and the origin). | polar coordinates |
| polar coordinate axes | A horizontal line and its origin. | polar coordinate axis |
| origin | The point where the coordinate axes intersect. | origin |
| baseline | The line where the base plane and the projection plane intersect. | basic line, ground line |
| Base plane | The horizontal plane on which the observer stands. | basic plane, ground plane |
| Fixed point | The foot of the perpendicular line drawn from the viewpoint to the base plane. Note : Sometimes referred to as the "standing point." | point of view |
| Viewpoint | The position of the eye when projecting an object. | observer’s eye, eye point |
| line of sight | The line connecting the viewpoint to a point in space, and its extension. | line of sight |
| Viewpoint, center of view | The point of intersection between the principal projection line and the projection plane. It serves as the vanishing point for all lines perpendicular to the projection plane (lines in the depth direction). | main point |
| view height | Projection height. | height of projection |
| Projection line | A straight line drawn through the viewpoint at the center of projection and a point on the object. The point of intersection on the projection plane represents the projection of that point on the object. | projection line |
| Principal projection line | A horizontal projection line passing through the viewpoint and intersecting the vertical projection plane and the center of the projection at right angles. | main projection line |
| Projection center | The point from which all projection lines originate. | projection centre |
| image | A representation of information drawn in a specific technical drafting format. Generally, it relates to a specific projection method or geometric figure. | representation |
| Horizon | The line where the horizontal plane intersects the vertical projection plane. It represents the geometric location of the vanishing point of all horizontal lines. | horizon line, horizontal line |
| vanishing point | The point at which parallel lines converge in perspective projection. An imaginary point at infinite distance where all parallel lines converge. | vanishing point |
| Distance points | The two vanishing points formed by parallel horizontal lines that make a 45-degree angle with the projection plane. | distance point |
| visual cone | A right circular cone with the principal projection line as its axis and the viewpoint as its apex. | vision cone |
| angle of vision | The vertex angle of the vision cone. | vision angle |
| vision circle | The circle where the projection plane intersects the cone of vision. | circle of vision |
| Orthogonal projection | A method of projection in which the projection center is placed at infinity and all projection lines are made parallel. | parallel projection |
| Orthogonal projection | A parallel projection in which the projection lines intersect the projection plane at right angles. | Orthogonal projection |
| Orthogonal projection | A parallel projection in which all projection lines intersect the projection plane at right angles. | orthogonal projection |
| Axial projection | A parallel projection of an object onto a single plane. | axonometric representation |
| Conformal projection | A projection in which all projection lines maintain the same angle with the three coordinate axes while projecting the object orthogonally onto a single projection plane. Since the projection plane intersects the coordinate axes at the same angle, the scale along all three axes is the same (monometric projection). | isometric axonometry |
| Isometric projection | A representation in which an object is orthogonally projected onto a single projection plane such that the scales along two coordinate axes are identical, while the scale along the third axis differs. | dimetric projection |
| Dimetric projection | A representation in which an object is projected parallel onto a single projection plane such that the scales along the three coordinate axes are all different. Note: This method is not recommended. | trimetric projection |
| Topographic projection | An orthographic projection onto a horizontal projection plane at the intersection of cross-sections of equal horizontal planes to represent a surface. Individual points are shown by contour lines that include the elevation of the point relative to the reference horizontal plane. | topographical projection |
| Mirror projection | A method of representing a figure by depicting the image of an object reflected in a mirror placed parallel to the object's coordinate plane. Note : A figure drawn in this manner is called a mirror projection. It is used in building ceiling plans, for example. | mirror projection |
| Oblique projection | A method of oblique projection onto a single projection plane. | oblique axonometry |
| Cabinet projection | A method of oblique projection onto a single projection plane such that the projection plane is parallel to one of the coordinate planes. Dimensions of objects on a plane parallel to the projection plane are shown on the same scale. By convention, the projection scale along the third axis is set to 1/2. | Cabinet axonometry |
| Caballier projection | A method of projecting onto a single projection plane such that the projection plane is parallel to one of the coordinate planes. Dimensions of objects on a plane parallel to the projection plane are shown at the same scale. By convention, the projection scale in the third axis direction is also set to the same scale (monometric projection). | cavalier axonometry |
| Central projection | A projection method in which the projection center is placed at infinity, causing all projection lines to converge. | central projection |
| Perspective projection | A projection in which projection lines connecting a viewpoint located at a certain distance from the projection plane to each point on the object intersect the projection plane. Notes : 1 . Generally, it is represented on a single projection plane. 2. A figure drawn using this method is called a perspective projection. | perspective projection, central projection |
| One-point perspective | A perspective representation in which one face of the object is parallel to the projection plane. | one-point perspective |
| Two-point perspective | A perspective projection in which the projection plane is vertical, the vertical faces of the object are inclined relative to the projection plane, and the horizontal faces are perpendicular to the projection plane. | two-point perspective |
| Three-point perspective | A perspective projection in which all surfaces of the object are inclined relative to the projection plane. | Three-point perspective |
| Bird's-eye perspective | A one-point perspective projection in which the projection plane is horizontal and the viewpoint is located above the projection plane. | bird’s-eye perspective, bird’s-eye view |
| Upward (overview) perspective projection | A one-point perspective projection in which the projection plane is horizontal and the viewpoint is below the projection plane. | frog’s eye perspective |
| Orthographic projection | An orthographic projection of an object placed perpendicular to its principal plane, which is parallel to one or more projection planes that coincide with or are parallel to the coordinate plane. Since these projection planes are rotated as convenient on the drafting paper, the projected figures of the object are placed symmetrically relative to each other. | orthographic projection |
| orthographic projection | A drawing created using orthographic projection. | orthographical drawing |
| Third-angle projection | An orthographic projection in which some or all of the other five projections of an object are arranged around the main projection of that object. Using the main projection as a reference, the other projections are arranged as follows: - The projection from above is placed at the top. - The projection from below is placed at the bottom. - The projection from the left is placed on the left. - The projection from the right is placed on the right. - The projection from the back is placed on the right or left. | third-angle projection (method) |
| First-angle method | An orthographic projection in which some or all of the other five projections of an object are drawn around the main projection of that object. Using the main projection as a reference, the other projections are arranged as follows: - The projection from above is placed below. - The projection from below is placed above. - The projection from the left is placed to the right. - The projection from the right is placed to the left. - The projection from the back is placed to the left or right. | first-angle projection (method) |
| Conformal projection | A representation in which an object is projected parallel onto a single projection plane so that the scales on the three coordinate axes are identical. | monometric projection (method) |
| Isometric diagram | A drawing created using isometric projection in which the lengths along the coordinate axes correspond to the actual lengths of the object. | isometric drawing |
| Oblique projection | Generally, a parallel projection in which all projection lines intersect the projection plane at the same angle other than 90°. | oblique projection (method) |
| Planar oblique projection | A drawing created by projecting onto a single projection plane so that the projection plane is parallel to the horizontal coordinate plane. | planometric axonometry |
| Perspective projection | A representation in which an object is projected onto a projection plane (usually a vertical plane) using central perspective. | perspective representation |
| Bird's-eye view | A one-point perspective projection with the viewpoint positioned high up. Note: The projection plane is generally a vertical or inclined plane; a horizontal plane is actually the exception. | bird’s-eye view |
| Arrow method | A method of presentation in which projection views and cross-sections can be freely placed within a drawing. Individual projection views and cross-sections are identified by repeating a capital letter near an arrow indicating the viewing direction on the main projection view. | reference arrow layout |
| X-ray projection | A pictorial representation using perspective. A drawing that depicts a complex object as if it were partially transparent, revealing its main features. | X-ray view |
| Pictorial representation | A two-dimensional representation that depicts the actual visible form of an object in a technical or artistic manner. In the field of drafting, axonometric projection and perspective projection are considered pictorial representations, just like perspective projection and exploded views. | pictorial drawing |
3.4 Terminology Related to Shapes
| Terminology | Definition | Corresponding English (for reference) |
|---|---|---|
| Outline Drawing | A diagram showing the outline of an object. | full view |
| Projection | A drawing created using projection methods. | projection view |
| Elevation | Projection onto a vertical plane (civil engineering, architecture). | Elevation |
| Front view | A projection view taken from the direction considered the front of the object. Also known as an elevation (Architecture). | Front view, front elevation |
| Plan view | A projection or horizontal cross-section of an object viewed from the top. Note: This is sometimes referred to as a top view. | plan |
| Side view | A projection view taken from the side of the object. | side view, side elevation |
| Bottom view | A projection of an object viewed from below. | Bottom view |
| Rear view | A projection view from the direction of the back of the object. | rear view, back elevation |
| Main projection | A projection selected to most clearly represent the shape and functional characteristics of an object. | principal view |
| auxiliary projection | A projection drawn in a coordinate system different from the object's own coordinate system. Note : Generally, a projection drawn in a position opposite the inclined plane. | relevant view, auxiliary view |
| Partial projection | A drawing representing a portion of a projection. | partial view |
| Local projection | A projection showing a specific part of an object, such as a hole or groove. | local view |
| Partial enlargement | A drawing in which only a specific part of the figure is enlarged and added to the main drawing. | elements on a larger scale |
| cross-sectional view | A drawing created by virtually cutting through an object and removing the front portion. It shows the cross-section as well as the outline of the object on the other side of the cut. | cut, sectional view |
| Full cross-sectional view | A drawing that shows all cross-sections obtained by cutting the object along a single plane, without omitting any. | full sectional view, full section |
| Cross-sectional view | A sectional view showing a cross-section perpendicular to the longitudinal direction. | drawing of cross section, cross-sectional view, lateral profile |
| Longitudinal section | a) A cross-sectional view in the longitudinal direction. b) A cross-sectional view along a river, road, or railway, developed to show height and other dimensions (civil engineering). | drawing of longitudinal section, longitudinal section profile |
| Single-sided cross-section | A drawing combining half of the outline drawing and half of the full cross-sectional view, with the object's centerline as the boundary. | Half-section view (half section) |
| Partial cross-section | A drawing in which the majority of the figure is shown as an outline, with only the necessary key sections depicted as cross-sections. | local sectional view (local section) |
| Rotated sectional view | A drawing in which a cross-section perpendicular to the projection plane of the figure is rotated 90 degrees and projected onto that plane. | revolved section |
| Cutting plane | The plane used to virtually cut through the object when drawing a sectional view. | cutting plane |
| cross-section | A figure showing only the outline of an object on one or more cutting planes. | section |
| Hatching | A group of parallel lines applied to a surface for the purpose of clearly indicating a cross-section or similar feature. | hatching |
| Symmetrical figure | A figure that is symmetrical with respect to a central line. | symmetrical part |
| Symmetry symbols | Two parallel lines drawn at either end of the center line of symmetry when only one side of a symmetrical figure is drawn. | - |
| Repetitive Figures | In a drawing of a single object, these figures represent instances where numerous elements of the same type and shape—such as bolt holes, pipe holes, or ladder rungs—are arranged in a regular pattern. | Repetitive features |
| Single-line representation | A method of depicting the cross-section or side view of a thin plate, or a wire, using a single thick line. | single-line delineation |
| Shadow | The dark areas formed on an opaque three-dimensional object when light is shone upon it. Note: The line indicating the edge of a shadow is called a shadow line. | shade |
| Shadow | The projection of a solid object's shadow onto a projection surface. Note: The line defining the outline of a shadow is called a shadow line. | shadow |
3.5 Terminology Related to Dimensions, etc.
| Terminology | Definition | Corresponding English (for reference) |
|---|---|---|
| Sequential Dimensioning | A method of entering the dimensions of individual parts one after another. | chain dimensioning |
| Parallel dimensioning | A method of entering the dimensions of individual parts side by side relative to a reference part. | parallel dimensioning |
| Cumulative dimensioning | A method of indicating the dimensions of individual parts relative to a reference point using a common dimension line. | Superimposed running dimensioning |
| Coordinate dimensioning | A method of indicating the position of individual points using coordinates. | dimensioning by coordinates, coordinate dimensioning |
| Dimensioning symbols | A symbol added to a dimension value to clarify the meaning of that dimension. | symbol for dimensioning |
| Reference | A point, line, or plane that serves as the basis for determining the shape of an object or the position of assembled parts. | reference |
| Assembly reference | A point, line, or plane used as a reference for assembly or installation. | reference point, reference line, reference plane |
| Origin symbol | A symbol representing the point with dimension 0 in progressive dimensioning and coordinate dimensioning. | symbol for origin |
| Dimension | A quantity representing the length, distance, position, angle, or size of a specific part in a specified direction. Reference : Dimensions include length dimensions, size dimensions, position dimensions, and angle dimensions. | dimension |
| size | A size dimension expressed using specified units and methods. | size |
| Length dimension | A dimension representing length. | linear dimension |
| Angular dimension | A dimension representing an angle. | Angular dimension |
| Position dimension | A dimension that indicates the position of a feature. | positional dimension |
| Functional dimension | Dimensions of parts of a shape or gaps that are essential for its function. | functional dimension |
| Representative dimension | Dimensions that represent the size and function of an object. | nominal size |
| Finished dimensions | The dimensions that an object should have after the machining intended in the manufacturing drawing has been completed. | finished dimension |
| Reference dimension | The dimension that serves as the basis for dimensional tolerances. | basic dimension, nominal dimension |
| Actual dimension | Actual dimensions of the finished object. | actual size |
| Reference dimension | Dimensions shown for reference rather than as requirements in the drawing. | auxiliary dimension, reference dimension |
| Taper | The degree of relative spread between two intersecting straight lines in a projection or cross-sectional view. | taper |
| slope | The degree of inclination of a line relative to a reference line in a projection or cross-sectional view. | slope |
| Dimension tolerance limits | The limits of a dimension within which the actual dimensions of a form are required to fall. Note : Indicated by permissible limit dimensions or by reference dimensions and dimensional tolerances. | permissible limits of dimension |
| Permissible limit dimensions | Two dimensions (maximum permissible dimension and minimum permissible dimension) that represent the permissible limits of a dimension. | limits of size |
| Dimension tolerance | The value obtained by subtracting the nominal dimension from the permissible dimensional limits. | permissible dimensional deviation |
| Dimensional tolerance | The difference between the maximum permissible dimension and the minimum permissible dimension. | dimensional tolerance |
| Manufacturing tolerance | The dimensional tolerance applied when manufacturing structural members or components (construction sector). | manufacturing tolerance |
| Assembly tolerance | Tolerance on dimensions relative to assembly standards (construction sector). | positioning tolerance |
| Positioning tolerance | Tolerance on dimensions used to determine the position of components relative to the assembly reference (construction sector). | positioning tolerance |
| General dimensional tolerance | A general dimensional tolerance specified collectively rather than by directly entering tolerances for individual dimensions in a drawing. It is primarily applied to dimensions that do not require special precision for functional purposes. | general dimension tolerance |
3.6 Terminology Related to Geometric Tolerances
| Terminology | Definition | Corresponding English Terms (for reference) |
|---|---|---|
| Geometric Characteristics | Characteristics that define shape, orientation, position, and runout. | geometrical characteristics |
| Geometry | Points, lines, axes, planes, and center planes subject to geometric tolerances. | feature |
| Independent feature | A feature for which geometric tolerances can be defined independently of any datum. For example, an axis for which straightness is a concern. | single feature |
| Associated feature | A feature that defines geometric tolerances in relation to a datum. For example, an axis for which parallelism is a concern. | related feature |
| Feature with Tolerance | A feature with geometric tolerances directly specified. | toleranced feature |
| Outer feature | A feature that defines the exterior of an object. For example, the outer diameter of a shaft. | external feature |
| Internal feature | A feature that defines the inside of an object. For example, the inner diameter surface of a hole. | internal feature |
| (Geometric tolerance) tolerance zone | The region defined by a geometric tolerance that specifies the area within which a feature with a tolerance must lie. | (geometrical) tolerance zone |
| Geometric tolerance | Permissible values for geometric deviations (deviations in form, orientation, and position, as well as runout). Note: For the definition of geometric deviation, refer to JIS B 0621. | geometrical tolerance |
| Shape tolerance | Geometrical tolerance for shape deviations of a form that should have a geometrically correct shape (e.g., a plane). | form tolerance |
| orientation tolerance | A geometric tolerance for deviations in the orientation of a feature that should have a geometrically correct orientation (e.g., parallel) relative to a datum. | orientation tolerance |
| Position tolerance | A geometric tolerance for the positional deviation of a feature that should have a geometrically correct positional relationship (e.g., coaxiality) relative to a datum. | location tolerance |
| True position | The exact position that a feature with a specified location tolerance should occupy relative to a datum. | true position |
| Runout tolerance | A geometric tolerance for the runout of a feature that should have a geometrically correct rotational plane (including a circular plane perpendicular to the datum axis line) centered on the datum axis line. | run-out tolerance |
| Datum system | A group of datums used by combining two or more datums individually to serve as a reference for a single related feature. Note : A datum system composed of three mutually orthogonal datum planes is specifically called a three-plane datum system. | datum system |
| Datum | A theoretically precise geometric standard established to regulate a feature’s positional tolerance, location tolerance, and runout tolerance. | datum |
| Datum body | The actual shape of the object used to establish a datum. | datum feature |
| datum target | A point, line, or defined area on an object with which machining, measuring, or inspection equipment or tools come into contact in order to establish a datum. | datum target |
| Theoretically accurate dimensions | An exact dimension used as a reference to determine the theoretical contour, position, or orientation when specifying the position or orientation of a form using geometric tolerances (tolerances for form, position, profile, and runout). | theoretically exact dimension |
| General geometric tolerance | Geometrical tolerances specified collectively rather than directly applied to individual features in a drawing. | general geometrical tolerance |
3.7 Terms Related to Dimensional Tolerances, Geometric Tolerances, and Surface Finishes
| Terminology | Definition | Corresponding English (for reference) |
|---|---|---|
| Envelope Condition | A condition stipulating that the solid of a single-body shape consisting of a cylindrical surface or two parallel planes must not extend beyond the envelope surface of the complete shape with the maximum solid dimensions. | envelope requirement |
| Perfect shape | A shape with no geometric deviations. | perfect form |
| Maximum material condition | A tolerance method that defines the interdependence between dimensional and geometric tolerances based on the maximum material condition. | maximum material requirement |
| Maximum material state | A state of a shape in which the permissible limit dimensions are such that the material volume of the shape is maximized. | maximum material condition (MMC) |
| maximum material dimension | The dimension that defines the maximum material state of a shape. Specifically, for external shapes, this is the maximum allowable dimension; for internal shapes, it is the minimum allowable dimension. | maximum material size (MMS) |
| Minimum material condition | The state of a shape with permissible limit dimensions such that the actual size of the shape is minimized. | least material condition (LMC) |
| Minimum material dimension | The dimension that defines the least material condition of a shape. Specifically, for external shapes, this is the minimum allowable dimension, and for internal shapes, it is the maximum allowable dimension. | least material size (LMS) |
| Effective condition | The limit of a complete shape resulting from the combined effect of the maximum material dimension of the target feature and its positional or orientation tolerances. | virtual condition (VC) |
| Effective dimension | A dimension that defines the effective condition of a feature. Specifically, for external features, it is the dimension obtained by adding the positional tolerance or location tolerance to the maximum permissible dimension. For internal features, it is the dimension obtained by subtracting the positional tolerance or location tolerance from the minimum permissible dimension. | virtual size (VS) |
| Minimum Substance Tolerance System | A tolerance system that defines the interdependence between dimensional tolerances and geometric tolerances based on the minimum material condition. | least material requirement |
| Surface finish | A general term referring primarily to surface roughness, grain direction, surface undulations, scratches, and indentations on the surfaces of machine parts, structural members, and the like. | surface texture |
| Design drawing | A drawing that illustrates the design intent and plan. | scheme drawing |
| Basic design drawing | Drawings used as a basis for final decisions and/or for review among the parties involved. | draft drawing, preliminary drawing |
| Construction drawings | Plans showing the design for the actual construction of a structure (civil engineering and architectural departments). | working drawing |
| Prototype drawing | Drawings intended for the prototyping of products or components. | prototype drawing |
| Manufacturing drawing | A drawing generally established as the basis for design data, showing all information necessary for manufacturing. | production drawing |
| Process drawing | A production drawing that depicts a stage in the manufacturing process or the entire sequence of processes. | process drawing |
| (Machining) process drawing | A process drawing that indicates the parts to be machined, machining methods, machining dimensions, and tools to be used in a specific manufacturing process. | - |
| Installation Drawing | A drawing that shows the general outline of an item and the information necessary for installing it in relation to the structure with which it is to be assembled or related items. | Installation Drawing |
| Construction Drawing | A fabrication drawing prepared for on-site construction (architecture sector). | working diagram |
| Detail drawing | A drawing that shows the shape, structure, or assembly and connection details of a specific part of a structure or component. Generally drawn to a large scale. | detail drawing |
| Kana-only drawing | A fabrication drawing (in the architectural field) shown using a vertical section of a building. | sectional detail drawing |
| Inspection drawing | A process drawing containing information necessary for inspection. | drawing for inspection |
| Order drawing | A drawing attached to an order form that specifies the order details, such as the size, shape, tolerances, and technical information of the product. | Order Drawing |
| Quotation drawing | A drawing attached to a quotation to show the client the details of the estimate. | drawing for estimate, estimation drawing |
| Drawing for approval | A drawing submitted to seek approval of the contents of a purchase order or similar document. | drawing for approval |
| Approved drawing | Drawings approved by the client or other parties. | Approved drawing |
| Explanatory drawing | A drawing used to explain structure, function, performance, etc. | explanatory drawing, explanation drawing |
| Reference drawing | A drawing used as a reference for equipment design in product manufacturing. | reference drawing |
| Record drawing | Drawings used to record details regarding the site, structure, assembled components, and the shape, materials, and condition of parts until completion. | as-built drawing, record drawing |
| General drawing | Drawings (in civil engineering and architectural departments) that depict the form and general structure of a structure using floor plans, elevations, and cross-sections. Note : These are typically drawn without using hidden lines. | General Drawing |
| Exterior drawing | A drawing showing the external shape, overall dimensions, and mass of an object, necessary for determining packaging, transportation, and installation conditions. | Outline Drawing |
| Developed drawing | A drawing in which the surfaces comprising the object are unfolded onto a plane. | development |
| Curved surface diagram | A drawing that represents complex curved surfaces, such as those of a ship's hull or a car body, using a set of lines. | lines |
| Grid drawing | A drawing in which a grid is added to allow for the identification of relative positions and module dimensions. | grid planning |
| Cross-section table | A table that collectively shows the cross-sections, shapes, and dimensions of columns and beams (architecture department). | - |
| Finish Schedule | A table that collectively lists the exterior and interior finishes of a building (Architecture Department). | Finish Schedule |
| Fittings Schedule | A table that collectively lists the locations, elevations, symbols, quantities, finishes, and hardware of doors and windows (Architecture Division). | Door and Window Schedule |
| Line drawings, diagrams | A drawing that uses symbols to illustrate the functions of a system’s components and their relationships. | diagram |
| System (line) diagram | A diagram showing systems such as water supply, drainage, and electricity. | system diagram |
| (Plant) Process Diagram | A diagram showing the machinery and equipment involved in the manufacturing process of a product, as well as the flow conditions (process steps), typically used in chemical plants. | - |
| Piping diagram | A diagram showing the actual connections and layout of pipes in structures and equipment. | Piping diagram, plumbing drawing |
| (Electrical) Wiring Diagram | A schematic diagram that uses symbols to illustrate the connections and functions of an electrical circuit. Note: The diagram is drawn without considering the shape, size, or position of individual components. | electrical schematic diagram |
| Instrumentation diagram | A schematic diagram showing the state in which measuring devices, control devices, and other equipment are installed and connected to industrial equipment or machinery. | instrumentation diagram |
| Wiring diagram | A schematic diagram showing the actual wiring configuration of a device or its components. Note : The diagram is drawn taking into account the shape, size, and position of each component. | connection diagram, wiring diagram |
| Structural diagram | A diagram showing the framework of machinery, bridges, etc., used for structural calculations. | Skeleton diagram |
| Motion diagram | A diagram showing the configuration and functions of a machine. | - |
| Mechanism diagram | A motion diagram that illustrates the structure of a machine using graphical symbols representing its constituent elements. | - |
| Functional diagram | A motion diagram that illustrates the functions of a machine using graphical symbols representing motion functions. | - |
| 3D Diagram | A general term for drawings created using orthographic projection, oblique projection, or perspective projection. | Single-view drawing |
| Exploded view | A pictorial representation of assembled components. Typically, it uses orthographic or perspective projection. Each component is drawn to the same scale and occupies its correct relative position. The components are separated and arranged in sequence along a common axis. | exploded view |
| Sketch | A drawing created freehand that does not necessarily adhere to scale. | freehand drawing |
| Part drawing | A drawing showing a single part that cannot be further broken down, containing all the information necessary to define the part. | Part drawing |
| Material drawing | A drawing showing the state of a mechanical part, such as a casting or forging, prior to machining. | drawing for blank |
| Assembly drawing | A drawing showing the relative positions of parts and the shapes of the assembled parts. | assembly drawing |
| Part correlation diagram | A drawing that provides information for the assembly and alignment of two parts. For example, it shows information regarding the dimensions, geometric tolerances, performance, and preliminary test requirements of both parts. | interface drawing |
| General assembly drawing | An assembly drawing showing all subassemblies and components of the finished product. | general assembly drawing |
| Subassembly drawing | An assembly drawing showing a partial structure consisting only of a limited number of parts or a group of parts. | Sub-assembly drawing |
| casting pattern drawing | A drawing depicting a pattern for casting made of wood, metal, or other materials. | pattern drawing |
| Component drawing, structural drawing | A drawing containing all the information necessary to define a single component. | component drawing |
| Component specification drawing | A drawing showing the dimensions, type, model number, and performance specifications of a component. | Component range drawing |
| Framework drawing | A structural drawing showing the installation positions, shapes, and dimensions of steel members and other components. | framing elevation |
| Foundation drawing | A drawing or set of drawings showing the foundation of a structure. | Foundation drawing |
| Site plan | A drawing showing detailed information on the location of buildings within an area and the placement of machinery and other equipment. | layout drawing, plot plan drawing |
| Site plan | A drawing showing the arrangement of structures, including their locations, reference points, and scale. | General Arrangement Drawing |
| Partial layout drawing | A drawing depicting a specific section of the general arrangement drawing, typically drawn to a larger scale to provide supplementary information. | partial arrangement drawing |
| Site plan | A drawing showing the site, the outline of structures, and their locations, typically in the context of urban planning. | block plan |
| Site plan | A drawing that indicates the location for construction work, including the site where a building will be constructed, access routes, and the general layout of the site, and also includes information regarding various utility facilities, roads, and site development. | site plan |
| Equipment layout | In the equipment manufacturing industry, a drawing showing the layout of each piece of equipment and the relationships between manufacturing processes. | plant layout drawing |
| Reinforcement drawing | A diagram or drawing showing the dimensions and placement of reinforcing bars (civil engineering and architectural sectors). | Reinforcement Arrangement Drawing, Reinforcement Schedule |
| As-built drawing | A drawing created by surveying terrain, structures, etc. (Civil Engineering, Architecture). | measured drawing, surveyed drawing |
| Demolition plan | A drawing showing which parts of a building or other structure are to be demolished and removed from the existing state (Architecture Division). | Demolition drawing |
| Drawing management | Management of operations related to drawings. Note : Operations related to drawings (including specifications, etc.) can be broadly categorized as follows: a) Registration, storage, issuance, and disposal of master drawings. b) Creation, editing, distribution, retrieval, and disposal of copies. c) Procedures for drawing revisions. d) Secondary master drawings and microfilm. | Administration of Drawings |
| Single-part drawing | A drawing depicting a single part or assembly on a single sheet of drawing paper. | individual system drawing, one-part one-sheet drawing |
| Multi-sheet drawing | A drawing in which a single part or assembly is depicted on two or more sheets of drawing paper. | multi-sheet drawing |
| Multi-item single-sheet drawing | A drawing depicting several parts or assemblies on a single sheet of drawing paper. | group system drawing, multi-part drawing |
| Master drawing | A drawing that provides currently approved information or data and records and documents the latest status. | original drawing |
| Secondary drawing | A drawing created by copying the original drawing, or a duplicate drawing. | - |
| Copy | The act of copying a drawing or diagram by placing tracing paper or similar material over it. | tracing |
| Drawing inspection | The act of inspecting a drawing or diagram. | check of drawing |
| Registration (of drawings) | A procedure performed by the drawing management department when accepting a completed drawing, as a means of management. | registration of drawing |
| Drawing register | A ledger that records the registration of drawings. The numbers assigned to newly registered drawings are determined from this ledger. | Drawings Register |
| Drawing card | A card used to manage drawings. | drawing card |
| Drawing number | A number assigned to each drawing. | drawing number |
| Sheet number | In the case of a multi-sheet drawing, a number used to distinguish each sheet. | sheet number |
| Drawing Catalog | A list of drawings to be issued, tabulating drawing numbers, titles, and other information. | drawings list |
| Issuing drawings | The act of issuing registered drawings. | Release of Drawing |
| Copy | A drawing created by copying the original drawing, or a drawing created from data as a hard copy or soft copy. | duplicated drawing |
| (Drawing) retrieval | The act of retrieving a required drawing from stored drawings in accordance with established procedures. | retrieval (of technical drawing) |
Appendix (For Reference) Terminology Related to Drafting Instruments and Drafting Paper
[Preface]
This Annex (for reference) provides terms and definitions related to general drafting equipment and drafting paper; it is not part of the standard.
[Scope]
This Annex provides terms and definitions related to drafting equipment and drafting paper used in general drafting.
| Terminology | Definition | Corresponding English (for reference) |
|---|---|---|
| Drawing Board | A flat board used to hold drafting paper during drafting. | drawing board |
| Drawing table | A stand that supports the drawing board. | drawing table |
| Drafting machines | A general term for machines that combine the functions of T-squares, set squares, protractors, and scales. | drafting machine |
| Track-type drafting machine | A drafting machine equipped with a parallel motion mechanism in which the X-axis and Y-axis move in unison. | track-type drafting machine |
| Link-type drafting machine | A drafting machine with a parallel motion mechanism using a pantograph-type linkage. | Link-type drafting machine |
| Pulley-type drafting machine | A drafting machine with a parallel motion mechanism using pulleys and belts. | Pulley-type drafting machine |
| CAD | A machine that performs drafting with the aid of a computer. | computer-aided drafting machine |
| Drafting instrument | An instrument used for drawing figures. | drawing instrument |
| Straightedge | A ruler used for drawing straight lines. | straight ruler |
| Straightedge | A long, flat ruler used for drawing straight lines. | straight ruler |
| parallel ruler | A ruler used for drawing parallel lines. | parallel ruler |
| T-square | A T-shaped, flat ruler used for drawing parallel lines or as a guide for a set square. | T-square |
| Triangular ruler | A triangular, flat ruler used for drawing straight lines. Note : Typically sold in sets of two, consisting of a 90° × 45° × 45° and a 90° × 60° × 30° ruler. | Triangle |
| Slope ruler | A ruler used to draw various gradients. | pitch scale |
| Curve ruler | A ruler used for drawing curves. | curved rulers |
| Cloud-shaped ruler | A flat curved ruler consisting of a series of connected curves. | French curve |
| R-ruler | A flat ruler with an arc as its outline. | Curved rulers |
| Adjustable curve ruler | A rod-shaped curve ruler used to draw arbitrary curves while maintaining a freely adjustable shape. | adjustable curve ruler |
| Thin, tapered curve rulers | A thin, angular curve ruler with varying thickness. | spline batten |
| template | A thin board used for tracing figures or characters. | template |
| scale | A ruler with measurement markings for measuring length. | scale |
| Flat scale | A scale with one or two types of measurement scales on one side. | flat bevel scale |
| Double-sided scale | A scale with four different types of scale markings on both sides. | double bevel scale |
| Triangular scale | A scale with a triangular cross-section and six types of scale markings. | triangular scale |
| logarithmic scale | A scale with logarithmic graduations. | logarithmic scale |
| Conformal scale | A scale used to draw isometric projections. | isometric scale |
| Protractor | A thin plate with angle markings used to measure angles. | protractor |
| Compass | An instrument used to draw circles or arcs. | compass |
| Center-wheel compass | A compass in which both legs open and close via a screw that rotates around a central pivot. | bow instrument |
| beam compass | An instrument designed to connect the central part and the arc-drawing part with a thin plate or similar material, used for drawing large circles or arcs. | beam compass |
| Elliptical compass | A compass used for drawing ellipses. | Ellipsograph |
| divider | An instrument used to transfer length measurements from a scale or figure to drawing paper, or to divide line segments. | dividers |
| proportional compass | A type of divider designed to facilitate the drawing of scaled or enlarged diagrams. | proportional dividers |
| Writing instruments | A general term for tools used to draw lines, numbers, and letters during drafting. | writing instruments |
| Drafting pen | A pen used for inking. | drawing pen |
| Drafting ink | Ink used for inking. | drawing ink |
| Inkwell | A tool used for inking. | ruling pen |
| Lead holder | A pencil designed to hold the lead in place with a chuck. | pencil lead holder |
| Erasing board | A thin board used to erase only a specific part of a drawing with an eraser. | Erasing shields |
| Drafting brush | A tool used to brush away eraser shavings. | drawing brush |
| Drafting paper | A general term for paper used in drafting. | drawing paper |
| tracing paper | Transparent or semi-transparent drafting paper. | tracing paper |
| Drafting film | A drawing film with low elasticity. | drawing film |
| Drawing tape | Tape used to secure drafting paper to a drafting board. | drafting tape |
Other Technical Documents
↓You can download the following technical documents as a single PDF file.
Specifications
Hole Machining, Tolerances, and Fits
Calculations, Conversions, Formulas, and Units
Machine Elements
- Hexagon Socket Head Cap Screw Standards List | Excerpt from JIS B 1176
- Shapes and Dimensions of Hexagon Socket Set Screws (Excerpt from JIS B 1177-1997)
- Shapes and Dimensions of Hex Bolts (Component Grade A) (Excerpt from JIS B 1180-1985)
- How to Use Hex Socket Set Screws
- Mechanical Properties of Steel Bolts and Screws (Excerpt from JIS B 1051-2000)
- Shapes and Dimensions of Hexagonal Wrenches (Hex Wrenches/L-Wrenches/Hex Wrenches) (Excerpt from JIS B 4648:2008)
- List of Standards for Dimensions and Tolerances of Parallel Keys and Keyways (Excerpt from JIS B 1301-1996/JIS B 1301-1959 [Old JIS])
- Snap Rings (C-Type Retaining Rings/C-Rings) Standards and Dimensions List (Excerpt from JIS B 2804-2010)
- Shim Dimensions
- Ball Bearing Standard Dimensions Table - JIS Excerpt
Material Properties
Terminology
- Glossary of Electromagnetic Clutch and Electromagnetic Brake Terms (Excerpt from JIS B 1404-1:2005)
- Glossary of Screw Terms (JIS B 0101:2013)
- Glossary of Fit Tolerances (Excerpt from JIS B 0401-1:2016)
- Glossary of Terms for Chains, Sprockets, and Accessories (Excerpt from JIS B 1812:2015)
- Glossary of Friction Belt Transmission Terms (Excerpt from JIS B 1860:2018)
- Technical Drawing—Terminology (Excerpt from JIS Z 8114:1999)