Remix and mix?

I've just been looking at tracklists, and I got to thinking... what's the difference between a mix and a remix?

They seem to be virtually the same thing (SEASONS "so happy so sad mix", SEASONS "Dub's Rain of duv remix"). They're both different versions of the song, right? I'm just not getting this.

Any help would be appreciated... that is, unless I didn't make sense. :x Thanks!