What it usually means: Wiener, bun, ketchup, snore.
What it means in Chicago: Wiener, bun, onions, relish, tomatoes, pickle, peppers, celery salt, mustard, and if you come near me with that ketchup I will just cut you. Why would you want ketchup on your hot dog when you already have tomatoes? That's like leaving your girlfriend for a blow-up doll.
OOPS: A true Chicago hotdog should also include some sweet pickle relish. An earlier version of this article did not include that ingredient. Our bad!