Definition:Linear Measure

Definition
Linear measure is the means of measurement of physical displacement.

It is one of the fundamental dimensions of physics.

In dimensional analysis it is assigned the symbol $$L$$ or $$\mathbf L$$.

Length
Length is distance measured in one direction. Usually, in multi-dimensional figures, the dimension in which the distance is longest is referred to as length.

It is the most widely used term for linear measure, as it is the standard term used when only one dimension is under consideration.

Breadth
Also known as width.

Breadth is distance measured in a second dimension, perpendicular to length and in the plane of the figure (in the case of a two-dimensional figure). In a three-dimensional figure, the choice of which direction is referred to as width is often arbitrary.

Depth
Depth is distance measured in a third dimension, perpendicular to both length and breadth. The choice of depth is often arbitrary, although in two-dimensional diagrams of three-dimensional figures, depth is usually the dimension perpendicular to the plane the figure is drawn in.

Distance
The term distance has a specialized meaning in analysis which has an immediate practical application in analytic geometry.