sea onion vs scilla

sea onion and scilla both are nouns.

Word	Noun	Adjective	Verb	Adverb
sea onion	Yes	No	No	No
scilla	Yes	No	No	No

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

sea onion: European scilla with small blue or purple flowers
scilla: an Old World plant of the genus Scilla having narrow basal leaves and pink or blue or white racemose flowers

Other hypernyms of sea onion include squill.

sea onion (noun)	scilla (noun)
European scilla with small blue or purple flowers	an Old World plant of the genus Scilla having narrow basal leaves and pink or blue or white racemose flowers
having dense spikes of small white flowers and yielding a bulb with medicinal properties