hero

from The American Heritage® Dictionary of the English Language, 5th Edition.

• noun In mythology and legend, a man, often of divine ancestry, who is endowed with great courage and strength, celebrated for his bold exploits, and favored by the gods.
• noun A person noted for feats of courage or nobility of purpose, especially one who has risked or sacrificed his or her life.
• noun A person noted for special achievement in a particular field: synonym: celebrity.
• noun The principal character in a novel, poem, or dramatic presentation.

from The Century Dictionary.

• noun In classical mythology, a superior being, distinguished from ordinary men chiefly by greater physical strength, courage, and ability, at the time of the Homeric poems still regarded as mortal, but from the time of Hesiod (about the eighth century b. c.) regarded as intermediate in nature between gods and men (a demigod), and immortal.
• noun A man of distinguished valor, intrepidity, or enterprise in danger; a prominent or central personage in any remarkable action or event; one who exhibits extraordinary courage, firmness, fortitude, or intellectual greatness in any course of action.
• noun The principal male personage in a poem, play, or story, or the person who has the chief place and share in the transactions related, as Achilles in the Iliad, Odysseus (Ulysses) in the Odyssey, Æneas in the Æneid.
• noun A person regarded as heroic; one invested by opinion with heroic qualities.

from the GNU version of the Collaborative International Dictionary of English.

• noun (Myth.) An illustrious man, supposed to be exalted, after death, to a place among the gods; a demigod, as Hercules.
• noun A man of distinguished valor or enterprise in danger, or fortitude in suffering; a prominent or central personage in any remarkable action or event; hence, a great or illustrious person.
• noun The principal personage in a poem, story, and the like, or the person who has the principal share in the transactions related; as Achilles in the Iliad, Ulysses in the Odyssey, and Æneas in the Æneid.
• noun extravagant admiration for great men, likened to the ancient worship of heroes.

from Wiktionary, Creative Commons Attribution/Share-Alike License.

• noun this sense?) A real or mythical person of great bravery who carries out extraordinary deeds.
• noun A role model.
• noun The main protagonist in a work of fiction.
• noun A large sandwich made from meats and cheeses; a hero sandwich.
• noun The product chosen from several candidates to be photographed.

from WordNet 3.0 Copyright 2006 by Princeton University. All rights reserved.

• noun (Greek mythology) priestess of Aphrodite who killed herself when her lover Leander drowned while trying to swim the Hellespont to see her
• noun a man distinguished by exceptional courage and nobility and strength
• noun someone who fights for a cause
• noun Greek mathematician and inventor who devised a way to determine the area of a triangle and who described various mechanical devices (first century)
• 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
• noun (classical mythology) a being of great strength and courage celebrated for bold exploits; often the offspring of a mortal and a god
• noun the principal character in a play or movie or novel or poem