Here is a message that I received from Suzanne Gieser about Plato:

I have read in several places that Plato was one of the first authors to use the term “archetype”. But I cannot find this concept in his works. I can find concepts like model, pattern, ideas and form. What would be the exact greek words that would correspond to the word “Archetype” and which passage in Plato’s texts could be refered to as using a concept like “archetype”?

Dear Suzanne, the word archetype comes from the Greek words arche (start, beginning, principle, origin) and typos (imprint, form, species, kind). The word is not used by Plato, although it appears already (at least) with the Lyric poet Simonides (Jac. 16, fr. 204 – not available online, so far as I know; the word appears in the first two lines, “Πραξιτέλης, ὃν ἔπασχε, διηκρίβωσεν ἔρωτ’ ἐξ ἰδίης ἕλκων ἀρχέτυπον κραδίης…” i.e. “Praxiteles discerned well the love that he was suffering, from his own heart drawing its archetype…”).