Inarchitecture, an apse (pl.: apses; from Latinabsis, 'arch, vault'; from Ancient Greekἀψίς, apsis, 'arch'; sometimes written apsis; pl.: apsides) is a semicircular recess covered with a hemispherical vaultorsemi-dome, also known as an exedra. In Byzantine, Romanesque, and GothicChristianchurch (including cathedral and abbey) architecture, the term is applied to a semi-circular or polygonal termination of the main building at the liturgical east end (where the altaris), regardless of the shape of the roof, which may be flat, sloping, domed, or hemispherical. Smaller apses are found elsewhere, especially in shrines.[1]
An apse is a semicircular recess, often covered with a hemispherical vault. Commonly, the apse of a church, cathedralorbasilica is the semicircular or polygonal termination to the choirorsanctuary, or sometimes at the end of an aisle.
In the Eastern Orthodox Church tradition, the south apse is known as the diaconicon and the north apse as the prothesis. Various ecclesiastical features of which the apse may form part are drawn together here.
The chancel (or sanctuary), directly to the east beyond the choir, contains the high altar, where there is one (compare communion table). This area is reserved for the clergy, and was therefore formerly called the "presbytery", from Greekpresbuteros, "elder", [citation needed] or in older and Catholic usage "priest".[3]
Semi-circular choirs, first developed in the East, which came into use in France in 470.[4] By the onset of the 13th century, they had been augmented with radiating apse chapels outside the choir aisle, the entire structure of apse, choir and radiating chapels coming to be known as the chevet (French, "headpiece").[5]
