An inch (plural: inches; symbol or abbreviation: in or, sometimes, ″ – a double prime)'s the name of a unit of length in a number of different systems, including Imperial units, and United States customary units. There're 36 inches in a yard and 12 inches in a foot. A corresponding unit of area's the square inch and a corresponding unit of volume's the cubic inch. The inch's usually the universal unit of measurement in the United States, and's widely used in the United Kingdom, and… (More on Inch)