An acre is equal to 43,560 square feet. An acre is a measurement of the area of a piece of land. The acre originated as a British unit of measure. It was originally measured as the amount of land a team of oxen could plow in one day.
The historical area represented by an acre varied from place to place. It became a standardized measurement equal to 1/640 of a square mile or 4,840 square yards. A 208.7-foot square plot equals one acre. Originally, the term used was "statute acre," but since this is the universal measurement now used in the U.S., the word "statute" has been dropped.