A pseudonym (often abbreviated pseud. when used in book publishing) is a fictitious alternative to a name. In some cases, pseudonyms are adopted because it is part of a cultural or organizational tradition, as in the case of devotional names used by members of some religious orders and "cadre names" used by Communist party leaders such as Trotsky and Stalin.

Pseudonyms are also used to hide an individual's identity, as with writers' pen names, graffiti artists, resistance fighters or terrorists' noms de guerre and computer hackers' handles. An example is of the well known fictional spy character James Bond concealing his identity by using the pseudonym "James St. John Smithe" and later "James Stock" in the film A View To A Kill.

Actors, musicians, and other performers sometimes use stage names, for example to mask their ethnic backgrounds. Stage names are also used to create a name which better matches their stage persona, as in the case of hip hop artists such as Ol' Dirty Bastard (who was known under at least six aliases); Black metal performers such as Nocturno Culto; and hardcore punk singers such as "Rat" of Discharge. Another example of a pseudonym is the name Lemony Snicket, an author who wanted to hide his identity.

A collective name or collective pseudonym is one shared by two or more persons. This is sometimes used by the co-authors of a work, such as Ellery Queen. The term is derived from the Greek ψευδώνυμον (pseudṓnymon), literally "false name", from ψεῦδος (pseûdos), "lie, falsehood" and ὄνομα (ónoma), "name".

A pseudonym is distinct from an allonym, which is the name of another actual person, assumed by someone in authorship of a work of art; such as when ghostwriting a book or play, or in parody, or when using a "front" name such as by screenwriters blacklisted in Hollywood in the 1950s and 1960s.

Similar to 0 things you like: