Room on a semi-circle, half ellipse or polygon plan, added to the body of the church and open to its interior. It usually closes the chancel, sometimes the aisles and the arms of the transept or westwork. The apse is usually smaller or equal to the block of a building that is closed by it. It was already in Roman architecture, from where it was taken over by Christianity and performed in the romanesque period. Gothic mostly used polygonal closures, which are sometimes referred to as apse. A small apse, added to a larger one, is called apsidiole.
