1) Unit of area 
A square inch (plural: square inches) is a unit of area, equal to the area of a square with sides of one inch. The following symbols are used to denote square inches: or in some cases `^2 The square inch is a common unit of measurement in the United States and the United Kingdom. ==Equivalence with other units of area== 1 square inch (assuming an....
[n] - a unit of area equal to one inch by one inch square
sq in noun a unit of area equal to one inch by one inch square