The word “church” is used three different ways in the Scriptures and we sometimes use it a fourth way. The context of how the word is used determines which of the four is being referred to.
“Church” could mean “the universal church,” meaning “all people who are Christians; Christ's body.”
Ephesians 1:22: “…and gave Him (Christ) to be the head over all things to the church.”
Ephesians 5:23: “…even as Christ is the head of the church.”
Colossians 1:18: “And He (Christ) is the head of the body, the church.”
Colossians 1:24: “…and fill up that which is behind of the afflictions of Christ in my flesh for His body's sake, which is the church.”
“Church” could mean “the local church,” meaning “the pastor and the congregation.”
The apostle Paul said in I Corinthians 4:17,
“…as I teach everywhere in every church”;
in I Corinthians 16:19,
“The churches of Asia salute you. Aquila and Priscilla salute you much in the Lord, with the church that is in their house”;
and in II Corinthians 11:28,
“Beside those things that are without, that which cometh upon me daily, the care of all the churches.”
(In Acts 20:17–18 we see that Paul called “the elders of the church” at Ephesus to come to him:
“And from Miletus he sent to Ephesus, and called the elders (pastors) of the church. And when they were come to him, he said unto them….”
The phrase “the church” here, means “the church at Ephesus” or “the body of Christ at Ephesus” or “the Christians at Ephesus.”
Ephesus was a large city. There were a number of congregations (local churches) in Ephesus. There was not just one “local church.” Each “local church” had an elder (a pastor). These elders (pastors) are the men that Paul called to come to himself at Miletus.)
“Church” could mean “the church service,” meaning “the meeting where people are gathered together to praise and worship God, to be taught the Word of God, to pray, etc.” We sometimes say, “We had church today,” or “What time does church start?,” or a mother may say to her children, “Sit still during church.”
I Corinthians 14:19:
“Yet in the church I had rather speak five words with my understanding, that by my voice I might teach others also, than ten thousand words in an unknown tongue.”
I Corinthians 14:28:
“But if there be no interpreter, let him keep silence in the church; and let him speak to himself, and to God.”
(We know these verses are not talking about a church building because they didn't even have church buildings back then.)
However, since we have “church buildings” in modern day, we sometimes use the word “church” to refer to “the church building,” meaning “the building where the local church (the pastor and the congregation) meets.” We sometimes say, “The pastor is down at the church,” or, “We have to paint the church this summer.”
Sometimes the word “church” is misused. When people say things like, “I have always been a part of the Lutheran church. I have lived in five different cities and been a member of five different Lutheran congregations,” or, “When I move to a new city, I always join a congregation that is a member of the Baptist church,” or, “The Methodist church has eight pastors with congregations in this area,” or, “The head office of the Assemblies of God church is located in Springfield, Missouri,” they are misusing the word. In the Bible (the Word of God), and in the context of Christianity, there is no such thing as “the Lutheran church” or “the Baptist church” or “the Methodist church” or the “Assemblies of God church.” These are “denominations” of Christianity. The proper word to use in this context is “denomination,” not “church.” (see What is a Denomination?)