Short for "hamburger" or "cheeseburger". It can also imply a soy burger or "Harvest Burger" veggie burger, in some contexts. Or a suffix in other contexts - "Gee, I hope Judge Jackson turns MS into Gatesburger", for instance. Also,&if you're watching a Perry Mason rerun, the name of Mason's prosecutor-nemesis Hamilton Burger, a man who became toast at the end of each episode. Are you getting hungry?

Not, as far as I know, used to denote "limburger".