- onion - edible bulb of an onion plant
--1 is a kind of bulb
--1 is a part of onion, onion plant, Allium cepa- onion, onion plant, Allium cepa - bulbous plant having hollow leaves cultivated worldwide for its rounded edible bulb
--2 is a kind of alliaceous plant
--2 has parts: onion
--2 has substances: isothiocyanate
--2 has particulars:- onion - an aromatic flavorful bulb
--3 is a kind of vegetable, veggie
--3 has particulars:Bermuda onion; green onion, scallion; Vidalia onion; Spanish onion; spring onion; shallot - onion, onion plant, Allium cepa - bulbous plant having hollow leaves cultivated worldwide for its rounded edible bulb