1 Answers
In biology, a homonym is a name for a taxon that is identical in spelling to another such name, that belongs to a different taxon.
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 ; 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.
Similarly, the International Code of Nomenclature for algae, fungi, and plants specifies that the first published of two or more homonyms is to be used: a later homonym is "illegitimate" and is not to be used unless conserved.