late 14c., in logic, "a previous proposition from which another follows, a judgment causing another judgment," from Old French premisse (14c.), from Medieval Latin praemissa(propositio or sententia) "(the proposition) set before," noun use of fem. past participle of Latin praemittere "send forward, put before," from prae "before" (see pre-) + mittere "to send" (see mission).
In legal documents it meant "matter previously stated" (early 15c.), which in deeds or wills often was a description of a house or building, hence the extended meaning "house or building, with grounds" (1730).
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Harper, D. (n.d.). Etymology of premises. Online Etymology Dictionary. Retrieved $(datetime), from https://www.etymonline.com/word/premises