Note 50 — Chapter VIII · ANALYTICA POSTERIORA II.
Reading edition
Analyt. Post. II. xiii. p. 97, b. 31: ὥσπερ δε ἐν ταῖς ἀποδείξεσι δεῖ τό γε συλλελογίσθαι ὑπάρχειν, οὕτω καὶ ἐν τοῖς ὅροις τὸ σαφές.
By τὸ σαφές, he evidently means the avoidance of equivocal or metaphorical terms, and the adherence to true genera and species. Compare Biese, Die Philosophie des Aristot. pp. 308-310.