hero (n.1) Look up hero at Dictionary.com
late 14c., "man of superhuman strength or physical courage," from Old French heroe (14c., Modern French héros), from Latin heros (plural heroes) "hero, demi-god, illustrious man," from Greek heros (plural heroes) "demi-god," a variant singular of which was heroe.

This is of uncertain origin; perhaps originally "defender, protector," and from PIE root *ser- (1) "to watch over, protect" (see observe). Meaning "man who exhibits great bravery" in any course of action is from 1660s in English. Sense of "chief male character in a play, story, etc." first recorded 1690s. First record of hero-worship is from 1774.

In Homer, of the Greeks before Troy, then a comprehensive term used of warriors generally, also of all free men in the Heroic Age. In classical mythology at least from the time of Hesiod (8c. B.C.E.) "man born from a god and a mortal," especially one who had done service to mankind; with the exception of Heracles limited to local deities and patrons of cities.
hero (n.2) Look up hero at Dictionary.com
1955, the New York City term for a sandwich elsewhere called submarine, grinder, poor boy (New Orleans), or hoagie (Philadelphia); origin unknown, perhaps so called for its great size (from hero (n.1)), or a folk-etymology alteration of Greek gyro as a type of sandwich.