onion

noun

on·​ion ˈən-yən 

plural onions

1

: a widely cultivated Asian herbaceous plant (Allium cepa) of the amaryllis family that has a pungent edible bulb and that is closely related to the garlic, chive, and leek

also : its bulb

2

: any of various usually ornamental alliums (such as Allium amplectens or A. caeruleum) related to the onion

oniony

ˈən-yə-nē 

adjective

an oniony flavor

oniony meatloaf

Examples of onion in a Sentence

The recipe calls for chopped onions.

He is growing onions in the garden this year.

The recipe calls for chopped onion.

Recent Examples on the Web

The Big Buford is made with two beef hamburger patties, two slices of American cheese, iceberg lettuce, tomato, red onion, dill pickles, ketchup, mustard, and mayo, all on a toasted bun. —Greta Cross, USA Today, 1 Apr. 2026

The red mesh sack, of the kind typically used to store oranges or onions, is stamped with her name, immigration number and date of deportation. —Mathew Miranda, Sacbee.com, 31 Mar. 2026

Monastic records from the twelfth century document the production of pickled onions and beets, which were stored in large earthenware jars to sustain communities through winter. —Literary Hub, 31 Mar. 2026

Six hours from now your dining room table will be bustling with friends waiting on your French onion soup for a dinner party. —Jesse Raub, Bon Appetit Magazine, 30 Mar. 2026

Word History

Etymology

Middle English, from Anglo-French oignon, from Latin union-, unio

First Known Use

14th century, in the meaning defined at sense 1

Phrases Containing onion

• Bermuda onion
• green onion
• onion dome
• onion ring
• pearl onion
• sea onion
• Spanish onion
• spring onion

Rhymes for onion

• trunnion

Kids Definition

onion

noun

on·​ion ˈən-yən 

: a widely grown Asian herb related to the lilies and having edible bulbs that have a sharp odor and taste and are used as a vegetable and to season foods

also : its bulb