Acre (Lat. ager, Ger. acker, a cultivated field), a standard measure of land, consisting in England and the United States of 4,840 square yards, or 48,564 square feet. In surveying, it is composed of 10 square chains, the measuring chain being 66 feet long. There are 640 acres in an English statute square mile. The Scotch acre is 1.27 of the English, and the Irish 1.62; the French and Belgian hectare, 2.47, and the arpent 0.99 (Geneva, 1.27); the Swiss faux, 1.62; the Spanish fanegada, 1.06; the Portuguese gueira, 1.43; the Austrian joch, 1.42; the Danish toende, 5.50; the Swedish tunneland, 1.13; the Russian desia-tina, 2.70. The morgen of Germany is generally about 0.65 of an acre, but it has heretofore varied in the different states from 0.63 to 2.40; in Holland it is 2.10, and in Poland 1.38. The moggia of Naples is 0.83 of an acre; the giornate of Sardinia, 0.93; the saccata of Tuscany, 1.22. The ancient Roman jugerum was 0.66 of an acre, and the Greek plethron 0.23.