flowering plant vs class Angiospermae

flowering plant and class Angiospermae both are nouns.

Word	Noun	Adjective	Verb	Adverb
flowering plant	Yes	No	No	No
class Angiospermae	Yes	No	No	No

flowering plant (noun)	class Angiospermae (noun)
plants having seeds in a closed ovary	comprising flowering plants that produce seeds enclosed in an ovary; in some systems considered a class (Angiospermae) and in others a division (Magnoliophyta or Anthophyta)