| Term | Definition |
| Gap | 1/16" should be left where extension line would join the object outline. |
| Radius Dimension | dimensions an arc |
| Arrowhead | dimension line and leader terminators |
| Dimension Line | is a thin, dark, solid line terminated by an arrowhead, indicating the direction and extent of a dimension. |
| Extension Line | is a thin, dark, solid line that extends from a point on the drawing to which a dimension refers |
| Center mark | are used to show and locate the centers of circular features. |
| Continue Dimension | A method of dimensioning in which dimensions appear in a line from one feature to the next |
| Baseline Dimension | A method of dimensioning in which several dimensions originate from a common surface, center line, or center plane. |
| Dimension Line Spacing | ASME standards recommend a minimum spacing of .375″(10mm) from a drawing feature to the first dimension line and a minimum spacing of .25″(6mm) between dimension lines. |
| Leader | thin, solid line directing attention to a note or dimension and starting with an arrowhead or dot. |
| Dimension Text Height | The ASME standard recommends a .12″(3mm) text height. |
| Diameter Dimension | dimensions a circle |
| Dimension Text | text using decimal-inch or metric values |
| Dimension | A description of the size, shape ,or location of features on an object or structure. |
