**Di*men"sion** (?), n. [L. *dimensio*, fr. *dimensus*, p. p. of *dimetiri* to measure out; *di- = dis-* + *metiri* to measure: cf. F. *dimension*. See Measure.]

**1.**

Measure in a single line, as length, breadth, height, thickness, or circumference; extension; measurement; -- usually, in the plural, measure in length and breadth, or in length, breadth, and thickness; extent; size; as, the **dimensions** of a room, or of a ship; the **dimensions** of a farm, of a kingdom.

Gentlemen of more than ordinary **dimensions**.
*W. Irving.*

Space of dimension, extension that has length but no breadth or thickness; a straight or curved line. -- Space of two dimensions, extension which has length and breadth, but no thickness; a plane or curved surface. -- Space of three dimensions, extension which has length, breadth, and thickness; a solid. -- Space of four dimensions, as imaginary kind of extension, which is assumed to have length, breadth, thickness, and also a fourth imaginary dimension. Space of five or six, or more dimensions is also sometimes assumed in mathematics.

**2.**

Extent; reach; scope; importance; as, a project of large **dimensions**.

**3.** Math.

The degree of manifoldness of a quantity; as, time is quantity having one **dimension**; volume has three **dimensions**, relative to extension.

**4.** Alg.

A literal factor, as numbered in characterizing a term. The term *dimensions* forms with the cardinal numbers a phrase equivalent to *degree* with the ordinal; thus, a2b2c is a term of five *dimensions*, or of the fifth degree.

**5.** pl. Phys.

The manifoldness with which the fundamental units of time, length, and mass are involved in determining the units of other physical quantities. Thus, since the unit of velocity varies directly as the unit of length and inversely as the unit of time, the **dimensions** of velocity are said to be length &divby; time; the **dimensions** of work are mass × (length)2 &divby; (time)2; the **dimensions** of density are mass &divby; (length)3.

<-- dimensional lumber -->
Dimension lumber, Dimension scantling, ∨ Dimension stock Carp., lumber for building, etc., cut to the sizes usually in demand, or to special sizes as ordered. -- Dimension stone, stone delivered from the quarry rough, but brought to such sizes as are requisite for cutting to dimensions given.

© Webster 1913.