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| Assembly | A group of machine or handmade parts that fit together to form a self-contained unit. |
| Assembly Drawing | A drawing that shows the various parts of an item when assembled. |
| Auxiliary View | An orthographic view of an object using a direction of sight other than one of the six basic views (front, top, right-side, rear, bottom, left-side); used to show a surface that is not parallel to any of the principal view planes. |
| Balloons | A circled number identifying each part shown in an assembly drawing. Also called a ball tag or bubble number. |
| Blind Hole | A hole that does not go completely through the workpiece. |
| Break Line | A line used to interrupt a drawing if an object will not fit on a drawing sheet. |
| Broken-Out Section | A section of an object broken away to reveal an interior feature for a sectional drawing. |
| Chamfer | A small angled surface formed between two surfaces. |
| Clearance Fit | A group of values that is used to analyze the distribution of data. |
| Component | A part or element of a larger whole. |
| Constraint | 1. A limit to a design process. Constraints may be such things as appearance, funding, space, materials, and human capabilities. 2. A limitation or restriction. |
| Counterbore | A cylindrical recess around a hole, usually to receive a bolt heard or nut. |
| Countersink | A conical-shaped recess around a hole, often used to receive a tapered screw. |
| Cutting Plane Line | A line drawn on a view where a cut was made in order to define the location of the imaginary section plane. |
| Degree of Freedom | The variables by which an object can move. In assemblies, an object floating free in space with no constraints to another object can be moved along three axes of translation and around three axes of rotation. Such a body is said to have six degrees of freedom. |
| Detail Drawing | A dimensioned, working drawing of a single part. Also referred to as part drawing. |
| Documentation | 1. The documents that are required for something, or that give evidence or proof of something. 2. Drawings or printed information that contains instructions for assembling, installing, operating, and servicing. |
| Exploded Assembly | An assembly drawing in which parts are moved out of position along an axis so that each individual part is visible. |
| Fillet | A rounded interior blend between two surfaces. Some uses are to strengthen joining surfaces or to allow a part to be removed from a mold. |
| Foreshorten | To show lines or objects shorter than their true size. Foreshortened lines are not perpendicular to the line of sight. |
| Formula | A mathematical relationship or rule expressed in symbols. |
| Full Section | A sectional drawing based on a cutting plane line that extends completely through an object. |
| Half Section | A sectional drawing based on a cutting plane line that cuts through one-quarter of an object. A half section reveals half of the interior and half of the exterior. |
| Interference | The amount of overlap that one part has with another when assembled. |
| Key | A rectangular or semicircular shape used to prevent parts, such as gears or wheels, from turning on a shaft. |
| Keyseat | A slot in a shaft to receive a key. |
| Keyway | A slot in a hub or material around a shaft that receives a key. |
| Parameter | A quantity which is fixed for the case in question but may vary in other cases. |
| Parametric modeling | A CAD modeling method that uses parameters to define the size and geometry of features and to create relationships between features. Changing a parameter value updates all related features of the model at once. |
| Parts List | A list of materials or parts specified for a project. Also referred to as a bill of materials or BOM. |
| Phantom Line | A line used to show the alternate positions of an object or matching part without interfering with the main drawing. |
| Ratio | The quantitative relation between two amounts showing the number of times one value contains or is contained within the other. |
| Rib | A relatively thin flat member acting as a brace support. Also called a web. |
| Rotation | Turning around an axis or center point. |
| Round | A rounded exterior blend between two surfaces. |
| Scale | 1. A straight-edged strip of rigid material marked at regular intervals and used to measure distances. 2. A proportion between two sets of dimensions used in developing accurate, larger or smaller prototypes, or models of design ideas. |
| Section Lines | Lines that are used to represent the material through which a cut is made in order to show an interior sectional view. |
| Sectional View | A drawing that shows the interior of an object as it would appear if cut in half or quartered. |
| Spotface | A shallow recess like a counterbore, used to provide a good bearing surface for a fastener. |
| Subassembly | An assembled part that is a part of a larger assembly. |
| Tap | To cut internal threads. |
| Taper | Gradual diminution of width or thickness in an elongated object. |
| Title Block | A table located in the bottom right-hand corner of an engineering drawing that identifies, in an organized way, all of the necessary information that is not given on the drawing itself. Also referred to as a title strip. |
| Translation | Motion in which all particles of a body move with the same velocity along parallel paths. |
| Working drawings | Drawings that convey all of the information needed to manufacture and assemble a design. |
