The term was used at least as early as Diogenes Laërtius, who called it (Plato's) "Theory of Ideas:" Πλάτων ἐν τῇ περὶ τῶν ἰδεῶν ὑπολήψει..., "Plato".
Istilah itu digunakan setidaknya paling awal pada zaman Diogenes Laertius, yang menyebutnya "Teori Idea" (Plato): Πλάτων ἐν τῇ περὶ τῶν ἰδεῶν ὑπολήψει...., "Plato".