heroyoudaoicibaDictYouDict[hero 词源字典]
hero: [14] Hero is a Greek word – hérōs – applied in ancient times to men of superhuman ability or courage, and in due course by extension to demigods. At first it was used in English simply to render this Greek notion, and it was not until the late 16th century that the extended and more general sense ‘brave or otherwise admirable man’ began to emerge. ‘Chief character in a story’ is a late 17th-century development.

English acquired the word via Latin hērōs as heros, but it was not long before this became interpreted as a plural, and a new singular hero was formed. Heroin [19] comes from German heroin, said to have been coined from the delusions of heroism which afflict those who take the drug.
=> heroin[hero etymology, hero origin, 英语词源]
hero (n.1)youdaoicibaDictYouDict
late 14c., "man of superhuman strength or physical courage," from Latin heros "hero," from Greek heros "demi-god" (a variant singular of which was heroe), 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. Sense of "chief male character in a play, story, etc." first recorded 1690s. First record of hero-worship is from 1774.
hero (n.2)youdaoicibaDictYouDict
1955, the New York term for a sandwich elsewhere called submarine, grinder, poor boy (New Orleans), or hoagie (Philadelphia); origin unknown, perhaps so called for its great size, or a folk etymology alteration of Greek gyro as a type of sandwich.