sea onion vs liliaceous plant

sea onion and liliaceous plant both are nouns.

Word	Noun	Adjective	Verb	Adverb
sea onion	Yes	No	No	No
liliaceous plant	Yes	No	No	No

As nouns, liliaceous plant is a hypernym of sea onion; that is, liliaceous plant is a word with a broader meaning than sea onion:

sea onion: having dense spikes of small white flowers and yielding a bulb with medicinal properties
liliaceous plant: plant growing from a bulb or corm or rhizome or tuber

sea onion (noun)	liliaceous plant (noun)
European scilla with small blue or purple flowers	plant growing from a bulb or corm or rhizome or tuber
having dense spikes of small white flowers and yielding a bulb with medicinal properties