till (prep.) Look up till at Dictionary.com
"until," Old English til (Northumbrian) "to," from Old Norse til "to, until," from Proto-Germanic *tilan (cognates: Danish til, Old Frisian til "to, till," Gothic tils "convenient," German Ziel "limit, end, goal"). A common preposition in Scandinavian, serving in the place of English to, probably originally the accusative case of a noun now lost except for Icelandic tili "scope," the noun used to express aim, direction, purpose (as in aldrtili "death," literally "end of life"). Also compare German Ziel "end, limit, point aimed at, goal," and till (v.).
till (v.) Look up till at Dictionary.com
"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 (cognates: 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.
till (n.) Look up till at Dictionary.com
"cashbox," mid-15c., from Anglo-French tylle "compartment," Old French tille "compartment, shelter on a ship," probably from Old Norse þilja "plank, floorboard," from Proto-Germanic *theljon. The other theory [Klein, Century Dictionary] is that the word is from Middle English tillen "to draw," from Old English -tyllan (see toll (v.)), with a sense evolution as in drawer (see draw (v.)).