Apse and Chancel

Apse noun - A domed or vaulted recess or projection on a building especially the east end of a church; usually contains the altar.

Chancel and apse are semantically related. In some cases you can replace term "Chancel" with "Apse", this nouns are similar.

Chancel noun - Area around the altar of a church for the clergy and choir; often enclosed by a lattice or railing.

Apse and chancel are semantically related. Sometimes you can replace term "Apse" with "Chancel", this nouns are similar.