A church is a house of worship built for any Christian denomination. The main purpose of a church is usually to hold liturgical ceremonies, known as masses or services. There is typically an altar at one end, so the usual arrangement is linear although several variations occur.

The original worship purpose concerns a Christian denomination. The usual altar-centered arrangement allows architectural variations without making one particular plan essential.

A Christian affiliation instead describes the religious connection of a place with another primary function. That connection alone does not make its building a church.