ATHENÆUM (Ἀθηνῶν), in Antiquity, a public place in which the professors of the liberal arts held their assemblies and gave instruction, the rhetoricians declaimed, and the poets rehearsed their performances. The three most celebrated Athenæa were those at Athens, at Rome, and at Lyons; the second of which was built by the Emperor Hadrian, and continued in high repute till the fifth century. The name Athenæum is frequently applied in modern times to establishments connected with literature and art, to public libraries, and the like.