class Dicotyledonae vs order Diapensiales

class Dicotyledonae and order Diapensiales both are nouns.

Word	Noun	Adjective	Verb	Adverb
class Dicotyledonae	Yes	No	No	No
order Diapensiales	Yes	No	No	No

class Dicotyledonae (noun)	order Diapensiales (noun)
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	used in some classifications: coextensive with family Diapensiaceae