noun the bishop's seat or throne, in ancient churches.
2. apse ·noun a reliquary, or case in which the relics of saints were kept.
3. apse ·noun a projecting part of a building, ·esp. of a church, having in the plan a polygonal or semicircular termination, and, most often, projecting from the east end. in early churches the eastern apse was occupied by seats for the bishop and clergy.