Rosidae vs class Dicotyledonae

Rosidae and class Dicotyledonae both are nouns.

Word	Noun	Adjective	Verb	Adverb
Rosidae	Yes	No	No	No
class Dicotyledonae	Yes	No	No	No

Rosidae (noun)	class Dicotyledonae (noun)
a group of trees and shrubs and herbs mostly with polypetalous flowers; contains 108 families including Rosaceae, Crassulaceae, Myrtaceae, Melastomaceae, Euphorbiaceae, Umbelliferae	comprising seed plants that produce an embryo with paired cotyledons and net-veined leaves; divided into six (not always well distinguished) subclasses (or superorders): Magnoliidae and Hamamelidae (considered primitive), Caryophyllidae (an early and distinctive offshoot), and three more or less advanced groups: Dilleniidae, Rosidae, Asteridae