Glossary entry

A scientific name of a taxon at the rank of species. A binomen, the combination of a generic name and a specific name (an interpolated name, such as a subgeneric name or an interpolated species-group name [Art. 6], when used, is not counted as one of the names in a binomen).

Source:
International Commission on Zoological Nomenclature (1999) International Code of Zoological Nomenclature. Fourth Edition. - International Trust for Zoological Nomenclature, XXIX + 306 pp.