In geometric measurements, length most commonly refers to the longest dimension of an object.
In certain contexts, the term "length" is reserved for a certain dimension of an object along which the length is measured. For example it is possible to cut a length of a wire which is shorter than wire thickness. Another example is FET transistors, in which the channel width may be larger than channel length.
Length may be distinguished from height, which is vertical extent, and width or breadth, which are the distance from side to side, measuring across the object at right angles to the length.
Length is a measure of one dimension, whereas area is a measure of two dimensions (length squared) and volume is a measure of three dimensions (length cubed). In most systems of measurement, the unit of length is a fundamental unit, from which other units are defined.
Famous quotes containing the word length:
“A playwright ... is ... the litmus paper of the arts. He’s got to be, because if he isn’t working on the same wave length as the audience, no one would know what in hell he was talking about. He is a kind of psychic journalist, even when he’s great.”
—Arthur Miller (b. 1915)
“At length to hospital
This man was limited,
Where screens leant on the wall
And idle headphones hung.
Since he would soon be dead
They let his wife come along
And pour out tea, each day.”
—Philip Larkin (1922–1986)
“When I had mapped the pond ... I laid a rule on the map lengthwise, and then breadthwise, and found, to my surprise, that the line of greatest length intersected the line of greatest breadth exactly at the point of greatest depth.”
—Henry David Thoreau (1817–1862)