Exedra

A semicircular stone or marble seat; a rectangular or semicircular recess; the portico of the Grecian palæstra, or gymnasium, in which disputations of the learned were held among the ancients; also, in private houses, the parastas, or vestibule, used for conversation. The term is sometimes applied to a porch or chapel which projects from a larger building. Also used, as synonymous with cathedra, for a throne or seat of any kind; for a small private chamber; the space between an oriel window and the small chapels between the buttresses of a large church or cathedral.