The inch (symbol: in or ″) is a unit of length in the British imperial and the United States customary systems of measurement.It is equal to 1 / 36 yard or 1 / 12 of a foot.Derived from the Roman uncia ("twelfth"), the word inch is also sometimes used to translate similar units in other measurement systems, usually understood as deriving from the width of the human thumb.

Definition of inch. (Entry 1 of 3) 1 : a unit of length equal to ¹/₃₆ yard — see Weights and Measures Table. 2 : a small amount, distance, or degree is like cutting a dog's tail off by inches — Milton …

every inch, in every respect; completely: That horse is every inch a thoroughbred.

inch, unit of British Imperial and United States Customary measure equal to 1/36 of a yard. The unit derives from the Old English ince, or ynce, which in turn came from the Latin unit uncia, which was “one-twelfth” of a Roman foot, or pes. (The Latin word uncia was the source of the name of another English unit, the ounce.)

The word inch in other languages is often similar to the word ‘thumb’, as thumb width was a measure used to define an inch – for instance King David 1 of Scotland defined the inch as being “the breadth of the thumb of a middle sized man, measured at the root of the nail’ .

inch definition: 1. a unit used for measuring length, approximately equal to 2.54 centimetres, sometimes shown by…. Learn more.

Every definition, being one of a group or series taken collectively; each: We go there every day. See more.

The British Standards Institute defined the inch as 25.4mm in 1930 in the document "Metric Units in Engineering: Going SI". In March 1932 the American Standards Association were asked to rule on whether to adopt the same value (at the time the American inch was 1/.03937 mm which approximated to 25.400051 mm).

Slope Conversion Tables 1/4 1/2 3/4 1 1-1/4 1-1/2 1-3/4 2 2-1/2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 0.25 0.50 0.75 1.00 1.25 1.50 1.75 2.00 2.25 3 4 5 6 7 8 9 10 ...