Other than its use as a noun (our moon) and a verb (to moon someone), 'moon' can be used as a way to say goodbye. It is short for "See you on the moon", a pseudo-common way to say goodbye.
Tim: Alright man, I have to leave.
Eric: Ok, we'll see you.
Tim: Yep, moon.
Somebody who has a perfectly round head
Verb (informal), used with or without an object: to consider or to think about; to mull
Note: may be used actively or passively.
Jack (to Marie): Are you down in the dumps for what happened?
Marie: Not at all. In fact, I don't want to moon it.
Slang/Cockney term for the '(JD) Wetherspoon' pub chain.
Cheeky pint at the moons tonight?
years, used in the bay area aka the yay area
i've known my man devin for many moons
to welch on a bet
You ever get paid on that bet?
Nah man, I got mooned by that fag.
the act of being rediculously pro/good looking at the game of counterstrike
moon be gettin that money, fools a nut.