order Polygonales vs class Dicotyledonae

order Polygonales and class Dicotyledonae both are nouns.

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

order Polygonales (noun)	class Dicotyledonae (noun)
coextensive with the family Polygonaceae	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