late 14c., "mark produced by pressure," also "image produced in the mind or emotions by something external," from Old French impression "print, stamp; a pressing on the mind" (13c.), from Latin impressionem (nominative impressio) "a pressing into, onset, attack," figuratively "a perception, mental impression," literally "a pressing into," from imprimere "press into or upon" (see impress (v.1)).
Meaning "act or process of making a mark upon the surface by pressing" is from early 15c.. Meaning "copy made by pressure from type or an engraving" is from 1550s; that of "printing of a number of copies, aggregate of copies printed at one time" is from 1570s. Meaning "belief, vague notion" (as in under the impression) is from 1610s.
updated on October 29, 2015