The Collaborative International Dictionary of English v.0.48:
Onion \On"ion\, n. [F. ognon, fr. L. unio oneness, unity, a
single large pearl, an onion. See One, Union.]
1. (Bot.) A liliaceous plant of the genus Allium (Allium
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
2. The flavor of an onion.
Onion fish (Zool.), the grenadier.
Onion fly (Zool.) a dipterous insect whose larva feeds upon
the onion; especially, Anthomyia ceparum and Ortalis
Welsh onion. (Bot.) See Cibol.
Wild onion (Bot.), a name given to several species of the