What does "classical" mean?

Classical: Of or pertaining to the ancient Greeks and Romans, esp. to Greek or Roman authors of the highest rank, or of the period when their best literature was produced; of or pertaining to places inhabited by the ancient Greeks and Romans, or rendered famous by their deeds. Though throned midst Latium's classic plains. Mrs. Hemans. The epithet classical, as applied to ancient authors, is determined less by the purity of their style than by the period at which they wrote. Brande & C. He [Atterbury] directed the classical studies of the undergraduates of his college. Macaulay.