A pseudonym is a fictitious alternative to a person's legal name (see alias). 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 Smith in the film A View To A Kill. Actors, musicians, and other performers sometimes use a stage name to mask their original ethnic background, particularly in the early to mid-1900s. 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.
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 Template:lang-el, pseudónymon – literally "given a name by error, lie name" from Template:lang-el, pseúdos – the lie and Template:lang-el, ónoma – the name); pseudo + -onym: false 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.
 Cultural or organizational traditions
In many monarchies, the sovereign is allowed to choose a regnal name by which he or she will be known. This official name may differ from his or her first name and may not even be one of his or her given names at birth.
A sovereign may choose not to use his or her first name for many reasons. Some, such as George VI of the United Kingdom (born Albert Frederick Arthur George), may wish to make a connection between their reign and that of a previous sovereign (in his case, his father, George V). Others, such as Queen Victoria (born Alexandrina Victoria of Kent), may never have been known by their original first name. Other sovereigns might select a regnal name to emphasize the legitimacy of the succession or even to indicate a change in policy or religion.
In Japan, the Emperor's personal name is never used as a regnal name: he is referred to by the name of his regnal era, and after his death his name is officially changed to that of the era. It is a severe breach of etiquette in Japan to refer to the current Emperor's personal name either in speech or in writing unless absolutely required by law. This does not apply to those outside Japan, however, which explains why Japanese and non-Japanese use different names for the Emperor. For instance, Emperor Hirohito was known within Japan as Emperor Showa.
In the tradition of various Roman Catholic religious orders and congregations, members abandon their birthname to assume a new, often unrelated, devotional name, often referring to an admired saint. For women, e.g., in the Society of the Helpers of the Holy Souls, this reflects the mystical marriage as bride of Christ. It is also common for a newly elected pope to assume a papal name. Most popes choose a name commemmorating an admired saint (Benedict XVI, for example), a predecessor or predecessors (John Paul I), or even a family member (John XXIII). However, a pope could theoretically choose any name as his papal name, including his own.
 Cadre names
Within Communist parties and Trotskyist organisations, noms de guerre are usually known as "party names" or "cadre names". While the practice originated during the revolutionary years after WW I, to conceal the identity of leaders, by the 1950s and 1960s, the practice was more of a tradition than an identity-concealment strategy. Some famous Communist Party names include Lenin (Vladimir Il'ich Ulyanov); Stalin (Yosif Vissarionovich Dzhugashvili); and Pol Pot (Saloth Sar).
 Political articles
From the late eighteenth to early nineteenth centuries, it was established practice for political articles to be signed with pseudonyms. A well-known American was the pen name Publius, used by Alexander Hamilton, James Madison, and John Jay, in writing The Federalist Papers. The British political writer Junius was never identified.
 Concealment of identity
 Literary pen names
A pen name (or "nom de plume") is a pseudonym adopted by authors or their publishers to conceal their identity. One famous example of this is Samuel Clemens writing under the pen name Mark Twain. A pen name may be used if a writer's real name is likely to be confused with the name of another writer or notable individual, or if their real name is deemed to be unsuitable. Authors who write in fiction and non-fiction, or in different genres, may use pen names to avoid confusing their readers, as in the case of mathematician Charles Dodgson, who wrote fantasy novels under the pen name Lewis Carroll.
Some female authors use male pen names, particularly in the 19th century, when writing was a male-dominated profession. The reverse is also true in the case of male romance novelists who use female pen names.
A pseudonym may also be used to hide the identity of the author, as in the case of exposé books about espionage or crime, or explicit erotic fiction. Some prolific authors adopt a pseudonym to disguise the extent of their published output, e.g., Stephen King writing as Richard Bachman. Co-authors may choose to publish under a collective pseudonym, e.g., P. J. Tracy and Perri O'Shaughnessy. Frederic Dannay and Manfred Lee used the name Ellery Queen as both a pen name and the name of their main character.
 Nom de guerre
"Noms de guerre" (French phrase meaning "war name") were frequently adopted by recruits in the French Foreign Legion as part of the break with their past lives and by members of the French resistance during World War II. These pseudonyms are often adopted by military special forces soldiers such as members of the SAS and other similar units, resistance fighters, terrorists and guerrillas to hide their identities and protect their families from reprisal. Some well-known noms de guerre include Andy McNab former SAS soldier, Carlos the Jackal for Ilich Ramírez Sánchez, Willy Brandt former Chancellor of West Germany and Subcomandante Marcos for the spokesman of the Zapatista Army of National Liberation (EZLN). [unverified]
 Brazilian martial arts
In capoeira, a Brazilian martial art, an apelido (pseudonym) is traditionally given to a capoeirista (Capoeira practitioner) at their first batizado, or promotion ceremony. Capoeiristas refer to each other almost exclusively by their apelidos, a tradition that dates back prior to Capoeira being legalized in Brazil. Since punishments were often harsh, it was used as a means of remaining anonymous and protecting fellow Capoeiristas from being caught, as well as minimizing any retribution directed towards their families. [unverified]
 Computer users
For a person using a computer online, a pseudonym can take the form of a handle, a user name, login name, avatar, or, sometimes, screen name or nickname (or "nick"). On the internet, pseudonymous remailers utilise cryptography that can be used to achieve persistent pseudonymity so that two-way communication can be achieved, and reputations can be established, without linking physical identities to their respective pseudonyms.[unverified]
In online gaming-clans, especially first-person "shooter games", in the demoscene, or in a distributed-computing project using Internet-connected computers, users or players can create "clan names" when joining, or add "clan tags" to their existing nicknames. In hacker culture, an individual can use a handle or "nym" (short for pseudonym) for public-identity purposes, while keeping his/her actual identity secret.[unverified]
 Stage names
 Film, theatre, and related activities
When used by an actor, performer or model, a pseudonym is a stage name or screen name. Actors who are members of a marginalized ethnic or religious group have often adopted stage names, typically changing their surname or entire name to mask their original background — as has been done in other fields as well. This phenomenon was common in the United States in the first half of the twentieth century. Screen names are also used to create a more marketable name, as in the case of Creighton Tull Chaney, who adopted the pseudonym Lon Chaney, Jr., a reference to his famous father Lon Chaney, Sr..
Pseudonyms are also used to comply with the rules of performing arts guilds (SAG, WGA, AFTRA, etc.), which do not allow performers to use an existing name, in order to avoid confusion. For example, these rules required film and television actor Michael Fox to add a middle initial and become Michael J. Fox, to avoid being confused with another actor named Michael Fox.
While most stage names are not used to conceal a person's identity, the exception is the pseudonym Alan Smithee, which is used by directors in the DGA to remove their name from a film they feel was edited or modified beyond their artistic satisfaction. In theatre, the pseudonym George or Georgina Spelvin, David Agnew and Walter Plinge are used to hide the identity of a performer. Professional names are also common for DJs in radio broadcasting.
 Porn stars
Many actors and actresses in pornographic films use pseudonyms to conceal their identity.
Musicians and singers use pseudonyms to allow artists to collaborate with artists on other labels while avoiding the need to gain permission from their own labels. Rock singer-guitarist George Harrison, for example, played guitar on Cream's song "Badge" using a pseudonym. In classical music, some record companies issued recordings under pseudonyms in the 1950s and 1960s to avoid paying royalties. A number of popular budget LPs of piano music were released under the pseudonym Paul Procopolis. Pseudonyms are also used as stage names in Metal bands, like Pig Benis in Mushroomhead, and "133" in Slipknot. Some of these names have meanings to them as well, like that of Brian Hugh Warner, more commonly known as Marilyn Manson. Marilyn coming from Marilyn Monroe, and Manson from convicted serial killer Charles Manson.
Most hip hop artists prefer to use a pseudonym that represents some variation of their name, personality, or interests. Prime examples include Ol' Dirty Bastard (who was known under at least six aliases), Diddy (formerly known as P. Diddy, and Puff Daddy), Ludacris, LL Cool J, Sam "Original Gangster" Biglari, and Chingy. Black metal artists also adopt pseudonyms, usually symbolizing dark values, such as Nocturno Culto, Gaahl, Abbath, and Silenoz. In punk and hardcore punk, singers and band members often replace their real names with more "tough"-sounding stage names, such as Sid Vicious of the late 1970s band Sex Pistols and "Rat" of the early 1980s band The Varukers and the 2000s re-formation of Discharge.
 Other types
Pseudonyms are also adopted for other reasons. In some cases, people choose a new name for political reasons. Some Jewish politicians adopted Hebrew family names upon making aliyah to Israel, dropping westernized surnames that may have been in the family for generations. David Ben Gurion, for example, was born David Grün in Poland. He adopted his Hebrew name in 1910, when he published his first article in a Zionist journal in Jerusalem. In the 1960s, black civil rights campaigner Malcolm X, (né Malcolm Little), adopted the 'X' to represent his unknown African ancestral name which was lost when his ancestors were brought to North America as slaves.
Famous pseudonyms of people who were neither authors nor actors include the architect Le Corbusier (né Charles Édouard Jeanneret); and the statistician Student (ne William Sealey Gosset), discoverer of Student's t-distribution in statistics.
When used by a radio operator, a pseudonym is a "handle," especially in Citizens' band radio.
On the Appalachian Trail it is common to adopt or, more usually, be given by others, a "trail name".