Definition of apse:
- 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.
- A reliquary, or case in which the relics of saints were kept.
- The bishop's seat or throne, in ancient churches.
- "The Ground Plan of the English Parish Church", A. Hamilton Thompson.
- "St. John's College, Cambridge", Robert Forsyth Scott.
- "The Story of Paris", Thomas Okey.