Word Origin & History
1552, "engagement or undertaking to do something," from L. stipulationem (nom. stipulatio), from stipulari "exact a promise." Traditionally said to be from L. stipula "straw," in ref. to some obscure symbolic act; this is rejected by most authorities, who, however, have not come up with a better guess.
Meaning "act of specifying one of the terms of a contract or agreement" is recorded from 1750.