basilica
The early Greek name for a royal palace. 2. A large oblong building with double columns and a semicircular apse at one end, frequently used by Christian emperors of Rome for religious purposes. Generally, they are oriented from east to west, with the apse in the east end to orient to the rising sun. That gave worshippers an opportunity to experience Christ in word, in eucharist, and in light. The shape differentiated the basilica from earlier pagan temples. Commonly the building had floor mosaics. Some leading examples include the Basilica of Maxentius, Rome; Santa Sabina, Rome; and Basilica of Sant’Apollinare Nuovo, Ravenna. Photo of San Lorenzo Basilica, Milan, 2019. (Webref.org)