tree onion vs Allium cepa viviparum

tree onion and Allium cepa viviparum both are nouns.

Word	Noun	Adjective	Verb	Adverb
tree onion	Yes	No	No	No
Allium cepa viviparum	Yes	No	No	No

As nouns, tree onion and Allium cepa viviparum are synonyms defined as:

tree onion and Allium cepa viviparum: type of perennial onion grown chiefly as a curiosity or for early salad onions; having bulbils that replace the flowers

Other synonyms of tree onion include Egyptian onion, top onion.

tree onion (noun)	Allium cepa viviparum (noun)
type of perennial onion grown chiefly as a curiosity or for early salad onions; having bulbils that replace the flowers	type of perennial onion grown chiefly as a curiosity or for early salad onions; having bulbils that replace the flowers