onion: Meaning and Definition of
on•ion
Pronunciation: (un'yun), [key] — n.
- a plant, Allium cepa, of the amaryllis family, having an edible, succulent, pungent bulb.
- any of certain similar plants.
- the bulb of the onion plant.
- the flavor or odor of this bulb.
- a person: He's a tough onion.
- to know one's subject or business thoroughly; be capable or proficient.
—adj. - containing or cooked with onions: onion soup.
- of, pertaining to, or resembling an onion.
Random House Unabridged Dictionary, Copyright © 1997, by Random House, Inc., on Infoplease.