late 14c., "a tax, duty, tribute," from Old French imposicion "tax, duty; a fixing" (early 14c.), from Latin impositionem (nominative impositio) "a laying on," noun of action from past participle stem of imponere "to place upon," from assimilated form of in "into, in" (from PIE root *en "in") + ponere "to put, place" (past participle positus; see position (n.)). Sense of "the act of putting (something) on (something else)" is from 1590s. Meaning "an act or instance of imposing" (on someone) first recorded 1630s, a noun of action from impose, which is unrelated to the earlier word.