A piece of land, containing 160 square rods, or 4,840 square yards, or 43,560 square feet. This is the English statute acre. That of the United States is the same. The Scotch acre was about 1.26 of the English, and the Irish 1.62 of the English.
A day's ploughing for one plough team. Now 200 X 22 yards. 120 were reckoned to be the average which would support one family, but the acre varied in real size according to local conditions and soil. (Wood, Michael. Domesday: A Search for the Roots of England, 213)