Dictionary.net

A measure of land of uncertain quantity mentioned in Domesday and other old books; by some called an "acre," by others "half an acre," and by others a "furlong." Spelman; Cowell; Blount. A French measure of land, containing one hundred square perches, of eighteen feet each, or about an acre. But the quantity varied in different provinces. Spelman. In Louisiana, the terms "arpent" and "acre" are sometimes used interchangeably; but there is a considerable difference, the arpent being the square of 192 feet and the acre of 209 and a fraction. Randolph v. Sentilles, 110 La. 419, 34 South. 587.