a Roman building, used for public administration, having a large rectangular central nave with an aisle on each side and an apse at the end
2.
a rectangular early Christian or medieval church, usually having a nave with clerestories, two or four aisles, one or more vaulted apses, and a timber roof
3.
a Roman Catholic church having special ceremonial rights
[C16: from Latin, from Greek basilikē hall, from basilikē oikia the king's house, from basileus king; see basil]