What is the nomenclature binomial?

It is the Linnean system for naming species, where each species has a Latinized name composed of two words: the first is the name of the genus and the second is the name of the species.
It is the system of scientific names applied to taxonomically ordered groups that constitute the object of systematics.
It is the sub-group that includes the typical taxon. Taxonomic species: abstract entity (taxonomic taxon); nominal species: species designated by its name (nominal taxon).