In zoological nomenclature, the valid name of a taxon is the correct scientific name for that taxon.[1] The valid name must be used for that taxon, regardless of any other name that may currently be used for that taxon, or may previously have been used. A name can only be valid (or invalid) when it is an available name under the International Code of Zoological Nomenclature (ICZN); if a name is unavailable, then it cannot be considered either valid or invalid.[2]
In contrast, a name which is available but not the correct name for a taxon is known as an invalid name.[3]
There are two categories of invalid names.