apse vs exedra

apse

noun
  • A semicircular projection from a building, especially the rounded east end of a church that contains the altar. 

  • The bishop's seat or throne in ancient churches. 

  • A reliquary, or case in which the relics of saints were kept. 

exedra

noun
  • A curved bench with a high back. 

  • A semicircular recess, with stone benches, used as a place for discussion. 

How often have the words apse and exedra occurred in a corpus of books? (source: Google Ngram Viewer )