aim (v.) Look up aim at Dictionary.com
c. 1300, "to estimate (number or size), calculate, count" (senses now obsolete), from Old French aesmer, esmer (Old North French amer) "to value, rate; count, estimate," ultimately from Latin aestimare "appraise, determine the value of" (see esteem (v.)).

Meaning in English apparently developed from "calculate," to "calculate with a view to action, plan," then to "direct a missile, a blow, etc." (late 14c.). Also used in Middle English of directing a letter, planting an altar, pitching a tent. Intransitive sense "intend, attempt" (early 14c.) was used by Shakespeare but is now considered colloquial. Related: Aimed; aiming.
aim (n.) Look up aim at Dictionary.com
late 14c., "a purpose, thing intended;" from aim (v.) or from nouns from the verb in Old French. Meaning "action of aiming" is from early 15c. To take aim originally was make aim (early 15c.).