Poaceae vs liliopsid family

Poaceae and liliopsid family both are nouns.

Word	Noun	Adjective	Verb	Adverb
Poaceae	Yes	No	No	No
liliopsid family	Yes	No	No	No

As nouns, liliopsid family is a hypernym of Poaceae; that is, liliopsid family is a word with a broader meaning than Poaceae:

Poaceae: the grasses: chiefly herbaceous but some woody plants including cereals, bamboo, reeds, sugar cane
liliopsid family: family of flowering plants having a single cotyledon (embryonic leaf) in the seed

Other hypernyms of Poaceae include monocot family.

Poaceae (noun)	liliopsid family (noun)
the grasses: chiefly herbaceous but some woody plants including cereals, bamboo, reeds, sugar cane	family of flowering plants having a single cotyledon (embryonic leaf) in the seed