What is the meaning of Apse?

The rounded east end of a church that contains or is behind the altar.

The interior portion of this section of the church building, excluding the ambulatory and any apse chapels.

A semicircular projection from any building that is similar to a church's apse.

The bishop's seat or throne in ancient churches.

A reliquary: a case in which the relics of saints are kept.

Obsolete form of apsis (“the nearest and furthest points to the centre of gravitational attraction for a body in orbit”).

An aspen tree.

aspen tree (esp. Populus tremula)

abscess

Source: wiktionary.org