What Does Religion Mean?

It is what you believe, or what you believe about spiritual matters.
In a general sense, it deals with the spiritual nature of man.
If you were raised a Catholic, you may believe that religion means only the Catholic beliefs and none other. I think it is OK to believe other things if you like, or just one thing if you like.
Most people consider that religion talks about how you conduct your life. Each named religion has a list of rules they think it is best to follow. These are the beliefs of that specific religion. All religions do not have the same rules. Just as even each person in a religion may act differently.
Most religions talk about God and give specific rituals to follow in their religion as they think is best.
In addition religion has to do with those things in your life you consider to be the most valuable. If you think about the nature of things, you may have a philosophy of religion. This would be a set of ideas you yourself have looked at, and arrived at concerning life. Older people usually like to hand these things down to younger folks, and of course the younger folk may not see the value in such things at the moment. But much later in life often reflect back and say, "Oh, that's what that means." They have found the meaning of what was said when they were young.

Religion is your faith.
Your explanation of why and how your on this earth.

Blind faith, corruption, irrationality, murder, hoax, intolerance, injustice, supernatural etc...