Question: "What is the definition of ekklesia?"
Answer: Understanding the definition of ekklesia (and its alternate spelling ecclesia) is an important component of understanding the church. Ekklesia is a Greek word defined as “a called-out assembly or congregation.” Ekklesia is commonly translated as “church” in the New Testament. For example, Acts 11:26 says that “Barnabas and Saul met with the church [ekklesia]” in Antioch. And in 1 Corinthians 15:9 Paul says that he had persecuted the church [ekklesia] of God.” The “called-out assembly,” then, is a congregation of believers whom God has called out of the world and “into His wonderful light” (1 Peter 2:9). The Greek ekklesia is the basis for our English words ecclesiastical (“pertaining to the church”) and ecclesiology (“the study of doctrine concerning the church”).
The word in the New Testament was also used to refer to any assembly of people. In his address to the Sanhedrin, Stephen calls the people of Israel “the assembly [ekklesia] in the wilderness” (Acts 7:38). And in Acts 19:39, ekklesia refers to a convening of citizens to discuss legal matters. However, in most contexts, the word ekklesia is used to refer to the people who comprise the New Testament church.
It is important that the church today understand the definition of ekklesia. The church needs to see itself as being “called out” by God. If the church wants to make a difference in the world, it must be different from the world. Salt is different from the food it flavors. God has called the church to be separate from sin (1 Peter 1:16), to embrace fellowship with other believers (Acts 2:42), and to be a light to the world (Matthew 5:14). God has graciously called us unto Himself: “‘Come out from them and be separate,’ says the Lord. ‘Touch no unclean thing, and I will receive you’” (2 Corinthians 6:17).