Inch

From Citizendium, the Citizens' Compendium

See also: U.S. customary units

The inch is a unit of length in the Imperial System and the U.S. customary system of units. An inch is equal to 1,000 thou, and twelve inches are equal to one foot. The inch is commonly abbreviated to in, although it is also often abbreviated to a double prime: ".

The inch was originally derived from the breadth of a man's thumb, although its precise definition has changed over the years as the two systems have evolved. The inch used today is the international inch, which is equal to 1/12 of a foot, or 2.54 centimetres.

Conversions

The inch is equal to:

1,000 thou, 1/12 foot, or 1/36 yard.

or

2.54 centimetres, 254 millimetres and multiples thereof.