In zoological nomenclature, a homonym is a zoological name that is identical in spelling to another such name, that belongs to a different taxon. The International Code of Zoological Nomenclature is a set of rules in zoology that have one fundamental aim: to provide the maximum universality and continuity in the naming of all animals according to taxonomic judgment. ... A taxon (plural taxa), or taxonomic unit, is a grouping of organisms (named or unnamed). ...

The rule in the International Code of Zoological Nomenclature is that the first such name to be published is the senior homonym and is to be used (it is "valid"); any others are junior homonyms and must be replaced with new names. It is, however, possible that if a senior homonym is archaic, and not in "prevailing usage," it may be declared a nomen oblitum and rendered unavailable, while the junior homonym is preserved as a nomen protectum. The International Code of Zoological Nomenclature (ICZN) is a set of rules in zoology that have one fundamental aim: to provide the maximum universality and continuity in classifying all animals according to taxonomic judgment. ... A nomen oblitum (Latin for forgotten name) is a name that has not been used in the scientific community for more than fifty years after its original proposal. ... // A conserved name or nomen conservandum (plural nomina conservanda) is a scientific name that enjoys special nomenclatural protection. ...

For example:

• Cuvier proposed the genus Echidna in 1797 for the spiny anteater.
• However, Forster had already published the name Echidna in 1777 for a genus of moray eels.
• Forster's use thus has priority, with Cuvier's being a junior homonym.
• Illiger published the replacement name Tachyglossus in 1811.

See also

• homonym
• homonym (botany)
• nomen oblitum
• nomen protectum