On"ion (?), n. [F. ognon, fr. L. unio oneness, unity, a single large pearl, an onion. See One, Union.]
(Bot.) A liliaceous plant of the genus
Allium (A. cepa),
having a strong-flavored bulb and long
hollow leaves; also, its bulbous root, much used as an
article of food. The name is often
extended to other species of the genus.
Onion fish (Zoöl.), the grenadier. -- Onion
fly (Zoöl.) a dipterous insect whose larva feeds upon the onion; especially, Anthomyia ceparum and Ortalis flexa. -- Welsh onion. (Bot.) See Cibol. -- Wild onion (Bot.), a name given
to several species of the genus Allium.
Hear it pronounced