subclass Arecidae vs class Monocotyledonae

subclass Arecidae and class Monocotyledonae both are nouns.

Word	Noun	Adjective	Verb	Adverb
subclass Arecidae	Yes	No	No	No
class Monocotyledonae	Yes	No	No	No

subclass Arecidae (noun)	class Monocotyledonae (noun)
one of four subclasses or superorder of Monocotyledones; comprises about 6400 species in 5 families of trees and shrubs and terrestrial herbs and a few free-floating aquatics including: Palmae, Araceae, Pandanaceae and Lemnaceae	comprising seed plants that produce an embryo with a single cotyledon and parallel-veined leaves: includes grasses and lilies and palms and orchids; divided into four subclasses or superorders: Alismatidae, Arecidae, Commelinidae, and Liliidae