What does Res mean in WoW? World of Warcraft Terms

Players of the popular MMO World of Warcraft may often hear the term “res” being used extensively. Contrary to what you might think, this does not refer to screen resolution or anything of that sort. Instead it is simply an abbreviation for “resurrection”. For example: “Don’t release, just wait for a res” means wait there for us to come resurrect you.
What on earth is a "res"?