Lets see what a New Testament church is according to Scripture.
About 100 of those times it is a specific local assembly and the other times it is either the church as an institution or eschatologically. A good example of this word is how we used to have in school an assembly. All the students would meet in the auditorium. Well when we were gathered we were an assembly and we were all part of that. But when we went back to out respective classes we were not at that time an assembly.