The Greek term translated into English as “church” is ἐκκλησία. It is used 114 times in the New Testament and fives uses refer to something other than the church of Jesus Christ. There has been some debate about the etymology of this term with earlier scholars employing a heavily diachronic approach. They have argued that the meaning of the term refers to those who have been called out of the world, based on the preposition ἐκ (“out of”) and the verb καλέω (“to call”). However while this may be true theologically to some degree, (and it preaches well), the method of how this is arrived at is invalid.
For instance, according to this type of methodology, if one examines the word ἐγκαλέω we would observe that the verb is built of the verb καλέω and the prefixed preposition ἐν and the meaning should be “to call in” or “call by.” However the lexical gloss for ἐνκαλέω is “to accuse,” something hardly affiliated with calling! In addition, the verb προκαλέω is from the verb καλέω and the preposition πρό (“before”) and while it does denote the sense “to call before,” the uses in secular Greek are almost all negative meaning “to provoke” and it’s only use in the New Testament is a prohibition to not challenge one another (Gal. 5:26).
So while the etymology of ἐκκλησία may be from ἐκ (“out of”) and the verb καλέω (“to call”), that does not mean that an ἐκκλησία means “a called out people” any more than adding “butter” and “fly” to give us a “butterfly” means a flying tub of Land O’Lakes. As a matter of fact, the overwhelming uses of καλέω (“to call”) and the related noun κλῆσις (“calling”) in the New Testament are used in soteriological passages and not ecclesiological ones. Lexical studies are far better served by a synchronic approach where how a term is used within the time frame of the word in question. Here we get a picture of how a word was being used by others at a particular time.
The term ἐκκλησία is the rendered 69 times in the Septuagint (LXX) for the Hebrew term qāhāl (קָהָל) which means “assembly.” When one examines the uses of ἐκκλησία in the LXX, we find that it can be used both of the people of God as well as the ἐκκλησία of the wicked!
Then Moses spoke in the hearing of all the assembly of Israel the words of this song, until they were complete (Deut. 31:30).
I hate the assembly of evildoers, And I will not sit with the wicked (Ps 26:5 [Psa. 25:5 – LXX]).
For instance, in secular Greek we see it used of various kinds of assemblies, even of animals! BDAG notes,
Remarkably, in Himerius, Or. 39 [Or. 5], 5 Orpheus forms for himself τὴν ἐκκλησίαν, a group of wild animals, who listen to him, in the Thracian mountains where there are no people), in our lit. of common interest in the God of Israel.
And in the New Testament it is used three times of an unruly mob (Acts 19:32, 39, 41). In many ways, ἐκκλησία is a term that needs to be qualified. Is it being used of an assembly of Israelites, an unruly mob who are set against the gospel, a pack of wild animals, or the church of Jesus Christ? In other words, only context can tell you what meaning is in view.
What we find in the secular Greek, the Greek of the LXX, and the New Testament regarding ἐκκλησία is a term that simply means an “assembly.” It is only after Jesus prophecies that he would build his ἐκκλησία (Matt. 16:18) does the term begin to take on this religious connotation.
Two major errors are often committed in lexical studies. One is the one we have just examined, that of root fallacy. When we try to determine meaning based a diachronic method where meaning is derived from etymology, we are susceptible to this mistake. Another error is that what James Barr called, “Illegitimate totality transfer,” where a word’s entire semantic range is read into every use of a word. It is incumbent upon the scholar not to read a meaning back into a word. In Acts 7:38, Stephen discusses the history of Israel and then refers to the “congregation (ἐκκλησία) in the wilderness.” Some have argued that since this passage uses ἐκκλησία, it supports the idea that “the church” was in existence in the Old Testament, even though it was future from the perspective of Matthew 16:18 and wasn’t gifted and empowered until Christ’s ascension (Ephesians 4:7-16) some 1500 years later.
This post may be fodder for another project but for now, it is a reminder that we should be careful not to be guilty of root fallacy because we run the risk of theological exegesis.
What is the church of Jesus Christ? It is his ἐκκλησία, his assembly of his people whom he has saved through faith alone in him alone.
 See Rod Decker, “Some Notes on Semantics, Illustrated with ἐκκλησία.” Retrieved @ file:///C:/Users/Dan/Documents/Documents/Documents/BBS/Dan’s%20teaching%20at%20BBS/NT%20506%20Exegetical%20Method/Resources/decker.semantics%20ill%20with%20εκκλησια.pdf. See also D. A. Carson, Exegetical Fallacies 2d ed. (Grand Rapids, 1996), who says that “specification of the meaning of a word on the sole basis of etymology can never be more than an educated guess,” 33.
 BDAG, s. v. “ἐκκλησία, 303.
 James Barr, The Semantics of Biblical Language (Oxford: Oxford University Press, 1961), 218.