Although Gk. ekklesía became a distinctively Christian word, it has both a Greek and an OT history. In the Greek world it was used of a public assembly summoned by a herald (< ek, “out,” and kaleín, “to call”; cf. Acts 19:32, 39f.). In the LXX it was used for the Heb. qāhāl, which denotes the congregation or people of Israel, especially as gathered before the Lord (cf. Acts 7:38). It is of interest that behind the NT term stand both Greek democracy and Hebrew theocracy, the two brought together in a theocratic democracy or democratic theocracy.

“Church” in The International Standard Bible Encyclopedia, Vol. 1, A-D, gen. ed. Geoffrey W. Bromiley, 693.