Thesaurus (Latin Vocabularius Expansionus) was a family of large sauropod dinosaurs that lived during the late Jurassic and early Cretaceous Periods of the Mesozoic Era. One of the largest herbivores ever discovered, Thesaurus is known for having an enormous number of similar species for each genus contained within the family.

Thesaurus was first discovered in 1904 by paleontologist Dr. Merriam Webster, in a region of the Southwestern United States known as Synonymia. Occasionally, bones of Thesaurus have also been found in the neighbouring region of Antonymia. Upon its initial discovery, the legitimacy of the find was challenged by famous dinosaur collector Robert Oxford, but he eventually conceded that “the Thesaurus is, in fact, an excellent companion to my own collection.”

Today, Thesaurus is one of the most famous dinosaurs, and is frequently cited by individuals in order to make themselves sound smarter than they appear. Thesaurus’ easily recognizable figure and placement in most school classrooms has lead to it becoming one of the most famous, eminent, celebrated, notable, popular, recognized, well-known dinosaurs.