nomen nudum
/ˌnəʊmɛn ˈnjuːdəm/ /ˌnəʊmən ˈnjuːdəm/Taxonomy
noun
A Latin name which was introduced without publication of an adequate description of the organism to which it was intended to be applied, or otherwise fails to conform to the appropriate code of biological nomenclature, and is therefore not available or valid as a result of that introduction. Occasionally: a vernacular name that cannot be attached to any species.
Origin
Late 19th century; earliest use found in American Naturalist. From scientific Latin nomen nudum from classical Latin nōmen + nūdum, neuter singular of nūdus.