The origin of the word “acre” lies in the historical English word “æcer” meaning “open field.” In the 1300s, an acre was equivalent to 40 perches, or rods, in length and four in breadth. This equals 220 yards by 22 yards. An acre was roughly the amount of land tillable by a yoke of oxen in one day.

Now, it is known all over the world as the unit of measurement for measuring land area. In the US & UK, a unit of acre equals 4,840 square yards, which are 0.405 hectares. Also, one acre equals ​1⁄640 (0.0015625) square miles, 43,560 square feet, and about 4,047 square meters.

The acre is also the statute unit in commonwealth countries like Canada, Antigua & Barbuda, Ghana, and Dominica. In South Asian countries like India and Pakistan, residential land/plots are measured in acres. Before, a Greek acre equaled 10,000 square Greek feet and a Turkish acre equaled 1,600 square Turkish paces. Now, both equal 1,000 square meters.