Orchidaceae vs genus Dendrobium

Orchidaceae and genus Dendrobium both are nouns.

Word	Noun	Adjective	Verb	Adverb
Orchidaceae	Yes	No	No	No
genus Dendrobium	Yes	No	No	No

Orchidaceae (noun)	genus Dendrobium (noun)
enormous cosmopolitan family of perennial terrestrial or epiphytic plants with fleshy tubers or rootstocks and unusual flowers	large genus and variable genus of chiefly epiphytic or lithophytic orchids of tropical and subtropical Asia and Australasia