allonym (n.)

word-forming element meaning "other," from Greek allos "other, different," cognate with Latin alius "other," from PIE root *al- (1) "beyond."

Proto-Indo-European root meaning "name."

It forms all or part of: acronym; allonym; ananym; anonymous; antonomasia; antonym; binomial; caconym; cognomen; denominate; eponym; eponymous; heteronym; homonym; homonymous; hyponymy; ignominious; ignominy; innominable; Jerome; matronymic; metonymy; metronymic; misnomer; moniker; name; nomenclature; nominal; nominate; noun; onomastic; onomatopoeia; paronomasia; paronym; patronym; patronymic; praenomen; pronoun; pseudonym; renown; synonym; synonymy; synonymous; toponym.

It is the hypothetical source of/evidence for its existence is provided by: Sanskrit nama; Avestan nama; Greek onoma, onyma; Latin nomen; Old Church Slavonic ime, genitive imene; Russian imya; Old Irish ainm; Old Welsh anu "name;" Old English nama, noma, Old High German namo, Old Norse nafn, Gothic namo "name."

"false name," especially a fictitious name assumed by an author to conceal identity, 1828, in part a back-formation from pseudonymous, in part from German pseudonym and French pseudonyme (adj.), from Greek pseudōnymos "having a false name, under a false name," from pseudēs "false" (see pseudo-) + onyma, Aeolic dialectal variant of onoma "name" (from PIE root *no-men- "name").

"Possibly a dictionary word" at first [Barnhart]. Fowler calls it "a queer out-of-the-way term for an everyday thing." Properly in reference to made-up names; the name of an actual author or person of reputation affixed to a work he or she did not write is an allonym. An author's actual name affixed to his or her own work is an autonym (1867). Related: Pseudonymity.