Etymology

From , from congregare "to herd together", itself from com- "together" + gregare "to collect into a flock, gather" (from grex "a flock, herd"); adopted c.1340 by the English Bible translator William Tyndale, to render the Greek (ekklesia) ('those called together, (popular) meeting'; hence Latin ecclesia 'church') in his New Testament, and preferred by 16th century Reformers instead of church

Noun

1. A gathering of faithful in a Christian church, Jewish synagogue, mosque or other place of worship. It can also refer to the people who are present at a devotional service in the building, particularly in contrast to the pastor, minister, imam, rabbi etc. and/or choir, who may be seated apart from the general congregation or lead the service (notably in responsary form).
2. A Roman Congregation, a main department of the Vatican administration of the universal church
3. A corporate body whose members gather for worship, or the members of such a body.
4. Any large gathering of people
5. The collective noun for eagles.