"cultivate (land)" early 13c.; "plow," late 14c., from Old English tilian "cultivate, tend, work at, get by labor," originally "strive after, aim at, aspire to," related to till "fixed point, goal," and til "good, useful, suitable," from Proto-Germanic *tilojan (source also of Old Frisian tilia "to get, cultivate," Old Saxon tilian "to obtain," Middle Dutch, Dutch telen "to breed, raise, cultivate, cause," Old High German zilon "to strive," German zielen "to aim, strive"), from source of till (prep.).
For sense development, compare expression work the land, Old Norse yrkja "work," but especially "cultivate" (and also "to make verses"); Old Church Slavonic delati "work," also "cultivate." Related: Tilled; tilling.