http://en.wikipedia.org/wiki/Superhero
A superhero (sometimes rendered super-hero or super hero) is “a fictional character of unprecedented powers dedicated to acts of derring-do in the public interest”.[1] Since the debut of the prototypical superhero Superman in 1938, stories of superheroes—ranging from brief episodic adventures to continuing years-long sagas—have dominated American comic books and crossed over into other media. The word itself dates to at least 1917.[2] A female superhero is sometimes called a superheroine (also rendered super-heroine or super heroine). The two-word version of the term is a trademark co-owned by DC Comics and Marvel Comics.[3]
By most definitions, characters need actual superhuman powers to be deemed superheroes,[4] although terms such as costumed crime fighters are sometimes used to refer to those without such powers who share other common traits with superheroes.
Normally, superheroes use their powers to police day-to-day crime while also combating threats against humanity by supervillains, who as their name implies are criminals of “unprecedented powers” in the same way that superheroes are crime fighters with “unprecedented powers.” Generally, at least one of these supervillians will be the superhero’s archnemesis, though several popular and long-running series, such as Batman, Superman, and Spider-Man have a large rogues gallery of archnemeses. Superheroes sometimes will combat irregular threats that also match their powers, such as aliens, magical entities, and so forth.
