A trinomen is a name consisting of three names: generic name, specific name and subspecific name. All three names are typeset in italics, and only the generic name is capitalised. No indicator of rank is included: in zoology, subspecies is the only rank below that of species.
If the generic and specific name have already been mentioned in the same paragraph, they are often abbreviated to initial letters: for example one might write, "The Great Cormorant Phalacrocorax carbo has a distinct subspecies in Australasia, the Black Shag P. c. novaehollandiae".
In a taxonomic publication, a name is incomplete without an author citation and publication details. This indicates who published the name; in what publication; with the date of the publication.
It must be noted that while binomial nomenclature came into being and immediately gained widespread acceptance in the mid-18th century, it was not until the early 20th century that the current unified standard of trinomial nomenclature was agreed upon, mainly due to its tireless promotion by Elliott Coues. See Allen (1884) for an example of the state of the debate and competing approaches in the late 19th century. Thus, when referring especially European works of the preceding era, remember that the nomenclature used is usually not in accord with contemporary standards.