diffs plural, not diff singular, because not everyone agrees 1. on what the differences are or 2. that there are major differences. i don't lose any sleep over it.

g

There are easy definitions that are widely accepted yet many people are confused.

Atheist: Lacks belief in any deities. NOTE: not the same as disbelieving, although calling it disbelief is a common semantic shortcut.

Agnostic: Lacks knowledge of any deities. NOTE: correctly speaking -- does not believe one CAN know anything about deities because they are inherently non-falsifiable.

The difference is that one describes the belief position about gods, the other, the knowledge position. They influence each other but can vary independently.

If you think gods are non-falsifiable then it's pretty hard to afford belief to them, and if you lack any god beliefs it's hard to stake a knowledge claim. So these are really just two side of the same coin.

It's easy:

Atheist (me): a person who does not believe in any gods.

Agnostic: doubts the existence of a god. A person who holds neither of two opposing positions on a topic.

"I don't believe in an invisible being that resides somewhere beyond the clouds," I say cheerfully to Christians who try to convert me.

Of course, it doesn't work. They always try to pin me.

"Can you see the wind?" a Christian zealot recently asked. "How do you know the wind exists if you can't see it?"

"Wind is scientifically proven and explained," I replied. "An invisible god is not."

I don't think so, but I don't know for sure.