Anything that's located above you is overhead — it’s literally over your head. An overhead compartment on an airplane is a good place to stash your carry-on suitcase. Overhead is also the money it takes to run a business.
Overhead works as both an adjective and an adverb: "An overhead view of the football field gives the spectators a better idea of the game, and a drone flying overhead is the perfect way to achieve it." There's also an overhead stroke in tennis, an overhead projector showing a movie in science class, and the overhead, or up-front expenses, that a new business requires.