This from my old blog, ten years back, bears repeating:
"It is quite true that the Greek word comes from two roots which mean literally 'called out.' Many preachers have made use of this fact to point out helpful spiritual implications, and yet by New Testament times the word carried no such denotation as 'called out.' It was simply the word for 'assembly' or 'congregation.' It so happened that in the Greek city-states an assembly of the citizenry resulted from the people being called out of their city and summoned from their farms to participate in such gatherings. Even though the etymology of the word remains, its real meaning is just 'assembly,' and a Greek-speaking person of New Testament times would be no more inclined to understand ekklesia in its original etymological value of 'called out' than we today would recognize 'God be with you' in 'good-by,' which, as we may learn from the dictionary, was derived from the longer phrase."
—Eugene A. Nida, God's Word in Man's Language [1952]
I do believe I transcribed it myself from my copy of the book.