early 14c., "to estimate, calculate," also "to intend," from Old French aesmer "value, rate; count, estimate," from Latin aestimare "appraise" (see estimation); current meaning apparently developed from "esteem," to "calculate," to "calculate with a view to action" (c.1400), then to "direct a missile, a blow, etc." (1570s). Related: Aimed; aiming.

early 14c., "target;" late 14c., "guess;" from aim, v.. Meaning "action of aiming" is from early 15c. (to take aim, originally make aim); that of "thing intended, purpose" is from 1620s.