onion

[ uhn-yuhn ]

noun

1. a plant, Allium cepa, of the amaryllis family, having an edible, succulent, pungent bulb.
2. any of certain similar plants.
3. the bulb of the onion plant.
4. the flavor or odor of this bulb.
5. Slang. a person:

   He's a tough onion.

adjective

1. containing or cooked with onions:

   onion soup.

2. of, relating to, or resembling an onion.

onion

/ ˈʌnjən /

noun

1. an alliaceous plant, Allium cepa, having greenish-white flowers: cultivated for its rounded edible bulb
2. the bulb of this plant, consisting of concentric layers of white succulent leaf bases with a pungent odour and taste
3. any of several related plants similar to A. cepa, such as A. fistulosum (Welsh onion)
4. know one's onions slang.
   to be fully acquainted with a subject

Derived Forms

• ˈoniony, adjective

Other Words From

• onion·like adjective
• onion·y adjective

Word History and Origins

Origin of onion¹

1325–75; Middle English onyon < Old French oignon < Latin ūniōn- (stem of ūniō ) a unity, large pearl, onion; union

Word History and Origins

Origin of onion¹

C14: via Anglo-Norman from Old French oignon, from Latin unio onion, related to union

Idioms and Phrases

Idioms

1. know one's onions, Slang. to know one's subject or business thoroughly; be capable or proficient.

More idioms and phrases containing onion

see know one's stuff (onions) .

Example Sentences

Representatives from The Onion told the New York Times that its bid was sanctioned by the families of the victims of the Sandy Hook Elementary School mass shooting, who successfully sued Jones for $1.4 billion in a defamation lawsuit.

From Salon

It was The Onion's bid that prevailed, though it declined to tell news outlets how much it paid.

From Salon

The lights will turn back on in January 2025, when Infowars is relaunched as a parody of itself that mocks “weird internet personalities” likes Jones who traffic conspiracy theories and health supplements, according to The Onion.

From Salon

The Onion, a satirical news site that satirizes current affairs and the journalists who cover it, said on Thursday that it had won the bankruptcy auction to control Infowars and other media outlets founded by Alex Jones, a far-right peddler of conspiracy theories.

From Salon

Onion and environmental samples from McDonald's stores and distribution centres have been collected by the FDA, the Colorado Department of Agriculture, and the Colorado Department of Public Health and Environment.

From BBC