Language is like humans. It lives, it breathes, it changes, and it dies. Unlike God who never changes, language is subjective and means different things to different people.
Unfortunately, within the church and in Christian circles, language is no more objective than it is outside of Christianity.
I mean, what did I even just say? What is the meaning of church, and what is a Christian? I know what I meant, but you may completely misunderstand what I meant because you might define those words differently than I did.