water lily vs hydrophyte

water lily and hydrophyte both are nouns.

Word	Noun	Adjective	Verb	Adverb
water lily	Yes	No	No	No
hydrophyte	Yes	No	No	No

As nouns, hydrophyte is a hypernym of water lily; that is, hydrophyte is a word with a broader meaning than water lily:

water lily: an aquatic plant of the family Nymphaeaceae
hydrophyte: a plant that grows partly or wholly in water whether rooted in the mud, as a lotus, or floating without anchorage, as the water hyacinth

Other hypernyms of water lily include aquatic plant, hydrophytic plant, water plant.

water lily (noun)	hydrophyte (noun)
an aquatic plant of the family Nymphaeaceae	a plant that grows partly or wholly in water whether rooted in the mud, as a lotus, or floating without anchorage, as the water hyacinth