To fry food is to cook it in very hot oil until it's crispy. For breakfast, you could fry yourself an egg, and maybe fry some bacon to go with it.
You can stir fry vegetables and deep fry doughnuts — and you have to be careful on a hot summer day not to (figuratively) fry yourself in the sun. When fry is a noun, it's usually short for "French fry," but it also means youngster, or "small fry." This less common meaning comes from Scottish, possibly from the Old Norse root frjo, "offspring."