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 dominant culinary approach was irreducibly Cajun: the meat was seared in a giant black pot with onions, bell peppers, and celery, and simmered in a broth heavily seasoned with hot sauce and spices—predominantly Tony Chachere’s Creole Seasoning, the regional improvement on salt and pepper. —Nathaniel Rich, Harpers Magazine, 20 Aug. 2025

The company issued a recall of its yellow onions in late October. —Meg Wingerter, Denver Post, 19 Aug. 2025

That accounts for about five percent of all onions consumed in the U.S. —Elly Fishman, Rolling Stone, 19 Aug. 2025

Fan out slices on plates or platter and top with onions (removed from skewers). —Cathy Thomas, Oc Register, 18 Aug. 2025

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