Lewis & Short

Ăristō, ōnis, m., = Ἀρίστων, a philosopher of Chios, a pupil of Zeno, founder of the sceptic philosophy, and contemporary of Cœsar, Cic. N. D. 3, 31, 77; id. Leg. 1, 13.
Hence, Aristōnēus, a, um, adj., of or pertaining to Aristo, Aristonean: vitia, Cic. Fin. 4, 15, 40.