Plato, Meno 74c

οὐκοῦν διὰ ταῦτα, ὅτι καὶ ἄλλα ἔστιν σχήματα; ναί. καὶ εἴ γε προσανηρώτα σε ὁποῖα, ἔλεγες ἄν; ἔγωγε. καὶ αὖ εἰ περὶ χρώματος ὡσαύτως ἀνήρετο ὅτι ἐστίν, καὶ εἰπόντος σου ὅτι τὸ λευκόν, μετὰ ταῦτα ὑπέλαβεν ὁ ἐρωτῶν· πότερον τὸ λευκὸν χρῶμά ἐστιν ἢ χρῶμά τι; εἶπες ἂν ὅτι χρῶμά τι, διότι καὶ ἄλλα τυγχάνει ὄντα; ἔγωγε. καὶ εἴ γέ σε ἐκέλευε λέγειν ἄλλα χρώματα, ἔλεγες

And for this reason—that there are other figures as well? Yes. And if he went on to ask you of what sort they were, you would tell him? I would. And if he asked likewise what color is, and on your answering white your questioner then rejoined: Is white color or a color? your reply would be: A color; because there are other colors besides. It would. And if he bade you mention other colors,