Old English æcer "tilled field, open land," from Proto-Germanic *akraz "field, pasture" (cf. Old Norse akr, Old Saxon akkar, Old Frisian ekker, Middle Dutch acker, Dutch akker, Old High German achar, German acker, Gothic akrs), from PIE *agro- "field" (cf. Latin ager "field, land," Greek agros, Sanskrit ajras "plain, open country").
Originally in English without reference to dimension; in late Old English the amount of land a yoke of oxen could plow in a day, afterward defined by statute as a piece 40 poles by 4, or an equivalent shape (5 Edw. I, 31 Edw. III, 24 Hen. VIII). Original sense retained in God's acre "churchyard."
is the translation of a word (tse'med), which properly means a yoke, and denotes a space of ground that may be ploughed by a yoke of oxen in a day. It is about an acre of our measure (Isa. 5:10; 1 Sam. 14:14).
unit of land measurement in the British Imperial and United States Customary systems, equal to 43,560 square feet, or 160 square rods. One acre is equivalent to 0.4047 hectares (4,047 square metres). Derived from Middle English aker (from Old English aecer) and akin to Latin ager ("field"), the acre had one origin in the typical area that could be plowed in one day with a yoke of oxen pulling a wooden plow. The Anglo-Saxon acre was defined as a strip of land 1 110 furlong, or 40 4 rods (660 66 feet). One acre gradually came to denote a piece of land of any shape measuring the present 4,840 square yards. Larger and smaller variant acres, ranging from 0.19 to 0.911 hectares, were once employed throughout the British Isles