It is called a kehillah, or (a bit less accurately) a tzibbur.
City Congregation for Humanistic Judaism was created in 1991.
It's called a synagogue congregation.
The word 'synagogue' means (Judaism) the place of worship for a Jewish congregation
Judaism is called Judaism.
A group of alligators is called a congregation or pod (of young).
The people attending a church service are called a congregation.
There is a Reform Synagogue in Chelmsford, Massachusetts, United States. It is called Congregation Shalom. Information about them can be found at their website at the Related Link.There is no synagogue in Chelmsford, Essex, United Kingdom. However, there is a congregation in nearby Brentwood called Rosh Tikvah which is affiliated with Liberal Judaism. Information about them can be found at their website at the Related Link.
The room is called a sanctuary, the seats are called pews
I don't know if there is a word that refers to a small group of people at a church, but I do know that a group of people at a church if you are referring to everyone in the church as a whole would be called a congregation.
A congregation of worshipers, an assembly or a gathering
They are called "Jews".
Congregation.