Religion is the idea of a combination of faith, search for understand, search for meaning, and community. There are other things that are also part of religion but I'm going to get ice cream, so I'm not taking the time to list them.
Church takes religion and defines each part of it, just as Islam takes religion and defines each part of it in ways that are different from Christianity. Religion is Christianity, Judaism, and Islam, but Islam, Christianity, and Judaism are not religion. I'm not sure if that makes sense, but I hope you get my meaning.