Plato, Laws 816b

πολλὰ μὲν δὴ τοίνυν ἄλλα ἡμῖν τῶν παλαιῶν ὀνομάτων ὡς εὖ καὶ κατὰ φύσιν κείμενα δεῖ διανοούμενον ἐπαινεῖν, τούτων δὲ ἓν καὶ τὸ περὶ τὰς ὀρχήσεις τὰς τῶν εὖ πραττόντων, ὄντων δὲ μετρίων αὐτῶν πρὸς τὰς ἡδονάς, ὡς ὀρθῶς ἅμα καὶ μουσικῶς ὠνόμασεν ὅστις ποτʼ ἦν, καὶ κατὰ λόγον αὐταῖς θέμενος ὄνομα συμπάσαις ἐμμελείας ἐπωνόμασε, καὶ δύο δὴ τῶν ὀρχήσεων τῶν καλῶν εἴδη κατεστήσατο, τὸ μὲν πολεμικὸν πυρρίχην, τὸ δὲ εἰρηνικὸν ἐμμέλειαν, ἑκατέρῳ τὸ

Many of the names bestowed in ancient times are deserving of notice and of praise for their excellence and descriptiveness: one such is the name given to the dances of men who are in a prosperous state and indulge in pleasures of a moderate kind: how true and how musical was the name so rationally bestowed on those dances by the man (whoever he was) who first called them all Emmeleiai, and established two species of fair dances—the warlike, termed pyrrhiche,