Definition of apses:
(n) :
(architecture) A semicircular projection from a building, especially the rounded east end of a church that contains the altar.
(n) :
The bishop's seat or throne in ancient churches.
(n) :
A reliquary, or case in which the relics of saints were kept.
(n) :
(obsolete or dialectal) An aspen tree.
(n) :
(astronomy) Obsolete form of apsis (“the nearest and furthest points to the centre of gravitational attraction for a body in orbit”). [(architecture) A recess or projection, with a dome or vault, at the east end of a church; an apse.]