1924, "make a photographic reproduction," from photo- "photographic" + copy (v.). The usual modern meaning arose 1942 with the advent of xerography. The noun is recorded from 1934. Related: Photocopied; photocopying.
late 14c., "make a copy of, duplicate" (a text or document), from Old French copier (14c.) and directly from Medieval Latin copiare "to transcribe," originally "to write in plenty," from Latin copia "plenty" (see copy (n.)). Hence, "to write an original text many times."
Figurative sense of "to imitate, to follow as an example" is attested from 1640s. Of computer data, by 1953. Meaning "send a copy (of a letter, later e-mail, etc.) to a third party" is attested by 1983. Related: Copied; copying.