hero (Noun) — Greek mathematician and inventor who devised a way to determine the area of a triangle and who described various mechanical devices (first century).
hero (Noun) — (Greek mythology) priestess of Aphrodite who killed herself when her lover Leander drowned while trying to swim the Hellespont to see her.
hero (Noun) — A man distinguished by exceptional courage and nobility and strength. ex. "RAF pilots were the heroes of the Battle of Britain"
hero (Noun) — The principal character in a play, movie, novel or poem.
hero (Noun) — Someone who fights for a cause.
hero (Noun) — (classical mythology) a being of great strength and courage celebrated for bold exploits; often the offspring of a mortal and a god.
hero (Noun) — A large sandwich made of a long crusty roll split lengthwise and filled with meats and cheese (and tomato and onion and lettuce and condiments); different names are used in different sections of the United States.