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:
“When one man has reduced a fact of the imagination to be a fact to his understanding, I foresee that all men will at length establish their lives on that basis.”
—Henry David Thoreau (1817–1862)
“At length upon the lone Chorasmian shore
He paused, a wide and melancholy waste
Of putrid marshes.”
—Percy Bysshe Shelley (1792–1822)
“Baltimore lay very near the immense protein factory of Chesapeake Bay, and out of the bay it ate divinely. I well recall the time when prime hard crabs of the channel species, blue in color, at least eight inches in length along the shell, and with snow-white meat almost as firm as soap, were hawked in Hollins Street of Summer mornings at ten cents a dozen.”
—H.L. (Henry Lewis)