Definition of "basilica"

(architecture) A Christian church building having a nave with a semicircular apse, side aisles, a narthex and a clerestory.  examples

A Roman Catholic church or cathedral with basilican status, an honorific status granted by the pope to recognize its historical, architectural, or sacramental importance.  examples

(obsolete) An apartment provided in the houses of persons of importance, where assemblies were held for dispensing justice; hence, any large hall used for this purpose.