Plato, Laws 895d

ἔχε δὴ πρὸς Διός· ἆρʼ οὐκ ἂν ἐθέλοις περὶ ἕκαστον τρία νοεῖν; πῶς λέγεις; ἓν μὲν τὴν οὐσίαν, ἓν δὲ τῆς οὐσίας τὸν λόγον, ἓν δὲ ὄνομα· καὶ δὴ καὶ ἐρωτήσεις εἶναι περὶ τὸ ὂν ἅπαν δύο. πῶς δύο; τοτὲ μὲν ἡμῶν ἕκαστον τοὔνομα προτεινόμενον αὐτὸ τὸν λόγον ἀπαιτεῖν, τοτὲ δὲ τὸν λόγον αὐτὸν προτεινόμενον ἐρωτᾶν αὖ τοὔνομα. ἆρά γε τὸ τοιόνδε αὖ βουλόμεθα νῦν λέγειν; τὸ ποῖον;

Now stop a moment, in Heaven’s name! Would you not desire to observe three points about every object? What do you mean? One point is the substance, one the definition of the substance, and one the name; and, moreover, about everything that exists there are two questions to be asked. How two? At one time each of us, propounding the name by itself, demands the definition; at another, propounding the definition by itself, he demands the name. Is it something of this kind we mean now to convey? Of what kind?