Glossary entry

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

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