Definition of "acre"

acre

/ˈeɪ.kə/

noun
plural acres or (UK colloquial) acre
1. An English unit of land area (symbol: a. or ac.) originally denoting a day's ploughing for a yoke of oxen, now standardized as 4,840 square yards or 4,046.86 square meters.
  Quotations
  Buried within the Mediterranean littoral are some seventy to ninety million tons of slag from ancient smelting, about a third of it concentrated in Iberia. This ceaseless industrial fueling caused the deforestation of an estimated fifty to seventy million acres of woodlands.
  2006, Edwin Black, chapter 2, in Internal Combustion‎
  1. (Chester, historical) An area of 10,240 square yards or 4 quarters.
2. Any of various similar units of area in other systems.
3. (informal, usually in the plural) A wide expanse.
4. (informal, usually in the plural) A large quantity.
5. (obsolete) A field.
6. (obsolete) The acre's breadth by the length, English units of length equal to the statute dimensions of the acre: 22 yds (≈20 m) by 220 yds (≈200 m).
7. (obsolete) A duel fought between individual Scots and Englishmen in the borderlands.