Plato, Cratylus, 394e
“Similarly so, my dear Hermogenes, it seems likely that the name of Orestes is properly founded, whether it be some chance which gave him his name, or some poet, who wished by that appellation to mark out the brutality, furor, and rugged mountain-man spirit (OREINON) of his nature.”

῞Ωσπερ γε καὶ ὁ “᾿Ορέστης,” ὦ ῾Ερμόγενες, κινδυνεύει ὀρθῶς ἔχειν, εἴτε τις τύχη ἔθετο αὐτῷ τὸ ὄνομα εἴτε καὶ ποιητής τις, τὸ θηριῶδες τῆς φύσεως καὶ τὸ ἄγριον αὐτοῦ
καὶ τὸ ὀρεινὸν ἐνδεικνύμενος τῷ ὀνόματι.