dinosaur vs archosaurian

dinosaur and archosaurian both are nouns.

Word	Noun	Adjective	Verb	Adverb
dinosaur	Yes	No	No	No
archosaurian	Yes	Yes	No	No

As nouns, archosaurian is a hypernym of dinosaur; that is, archosaurian is a word with a broader meaning than dinosaur:

dinosaur: any of numerous extinct terrestrial reptiles of the Mesozoic era
archosaurian: extinct reptiles including: dinosaurs, plesiosaurs, pterosaurs, ichthyosaurs, thecodonts

Other hypernyms of dinosaur include archosaur, archosaurian reptile.

dinosaur (noun)	archosaurian (noun)
any of numerous extinct terrestrial reptiles of the Mesozoic era	extinct reptiles including: dinosaurs, plesiosaurs, pterosaurs, ichthyosaurs, thecodonts

dinosaur (adjective)	archosaurian (adjective)
	of or relating to reptiles of the subclass Archosauria