The other definition listed is only partial. It can mean "huh?", but it is not terrible common. We usually just say "huh?" in Canada. "Eh?" is a word you add to the end of a sentence, to ask for a response of agreement or disagreement, similar in meaning to "don't you think?"
"Looks like a storm comin' in, eh?"
It is also sometimes used with "I know", and in that case it doesn't really mean anything.
-"Wow, the Flames really kicked ass tonite!"
-"I know, eh?"
Good luck trying to use it properly if you're not Canadian. Trust me Americans, we can tell the difference! You're not foolin' anybody :)