ATHENÆUM, in antiquity, a public place wherein the professors of the liberal arts held their assemblies, the rhetoricians declaimed, and the poets rehearsed their performances. These places, of which there were a great number at Athens, were built in the manner of amphitheatres, encompassed with seats, called cunei. The three most celebrated Athenæa were those at Athens, at Rome, and at Lyons; the second of which was built by the emperor Adrian.