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

Add beef, garlic, and onion; cook until beef is browned, stirring occasionally to crumble, 6 to 8 minutes. —Ann Taylor Pittman, Southern Living, 2 May 2025

Place tomatillos, onion, garlic and jalapenos on the sheet, drizzle with olive oil and sprinkle with salt and pepper. —Jess Fleming, Twin Cities, 27 Apr. 2025

Salt brings out the richness of the avocado, the brightness of the lime and cilantro, and the zip of onion, garlic, and peppers. —Karla Walsh, Better Homes & Gardens, 27 Apr. 2025

Radishes, onions, garlic, fennel bulbs and jicama are especially low-sugar options. —Dr. Steven Gundry, CNBC, 25 Apr. 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