By most definitions, characters need not have actual superhuman powers to be deemed superheroes, although terms such as costumed crimefighters are sometimes used to refer to those without such powers who share other common traits with superheroes.

The two-word version of the term is a trademark co-owned by DC Comics and Marvel Comics.

Common traits

• Extraordinary powers and abilities, relevant skills, and/or advanced equipment. Although superhero powers vary widely, superhuman strength, the ability to fly, enhanced senses, and the projection of energy bolts are all common. Some superheroes, such as Batman and the Question possess no superhuman powers but have mastered skills such as martial arts and forensic sciences. Others have special weapons or technology, such as Iron Man's powered armor suits and Green Lantern's power ring. Many characters supplement their natural powers with a special weapon or device (e.g., Wonder Woman's lasso and bracelets, Spider-Man's webbing, Wolverine's adamantium, Daredevil's billy club, Thor's hammer, Gambit's staff, etc.)
• A strong moral code, including a willingness to risk one's own safety in the service of good without expectation of reward. Such a code often includes a refusal or strong reluctance to kill or wield lethal weapons.
• A motivation, such as a sense of responsibility (e.g. Spider-Man), a formal calling (e.g., Wonder Woman), a personal vendetta against criminals (e.g. Batman), or a strong belief in justice and humanitarian service (e.g. Superman).
• A secret identity that protects the superhero's friends and family from becoming targets of his or her enemies (exceptions such as the Fantastic Four notwithstanding), such as Clark Kent (Superman), although many superheroes have a confidant (usually a friend or relative who has been sworn to secrecy). Most superheroes use a descriptive or metaphoric code name for their public deeds.
• A distinctive costume, often used to conceal the secret identity (see Common costume features).
• An underlying motif or theme that affects the hero's name, costume, personal effects, and other aspects of his or her character (e.g., Batman resembles a large bat, calls his specialized automobile, which also appears bat-like, the "Batmobile" and uses several devices given a "bat" prefix).
• A supporting cast of recurring characters, including the hero's friends, co-workers and/or love interests, who may or may not know of the superhero's secret identity. Often the hero's personal relationships are complicated by this dual life, a common theme in Spider-Man and Batman stories in particular.
• A number of enemies that he/she fights repeatedly. In some cases superheroes begin by fighting run of the mill criminals before super villains surface in their respective story lines. In many cases the hero is in part responsible for the appearance of these super villains (The Scorpion was created as the perfect enemy to defeat Spider-Man, and characters in Batman's comics often accuse him of creating the villains he fights). Often superheroes have an archenemy who is more troubling than the others. Often a nemesis is a superhero's doppelganger or foil (e.g., Sabretooth embraces his savage instincts while Wolverine tries to control his. Batman is serious and grim, while the Joker is flamboyant and views the world as one big sick joke).
• Independent wealth (e.g., Batman or the X-Men's benefactor Professor X) or an occupation that allows for minimal supervision (e.g., Superman's civilian job as a reporter).
• A headquarters or base of operations, usually kept hidden from the general public (e.g., Superman's Fortress of Solitude, Batman's Batcave).
• A backstory that explains the circumstances by which the character acquired his or her abilities as well as his or her motivation for becoming a superhero. Many origin stories involve tragic elements and/or freak accidents that result in the development of the hero's abilities.