Ekklēsia: A Greek term usually translated as “church,” “gathering,” “assembly,” or “congregation.”

Outside of Scripture it could stand for any group that assembles; in the Septuagint it occasionally refers to the qāhāl of Israel (the people of Israel assembled to hear the word of God).

In the NT it became a standard term for the church.

Patzia & Petrotta, Pocket Dictionary of Biblical Studies (2002), 40.