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 meal prepper and avid home cook is bound to love this manual food processor that can effortlessly chop, dice, nearly puree garlic, tomatoes, avocado, onions, and other foods. —Alicia Geigel, Southern Living, 9 Apr. 2025

Add mushrooms, onion, salt, and pepper to the skillet and cook 5 to 7 minutes, until mushrooms are softened and caramelized. —Sarah Martens, Better Homes & Gardens, 9 Apr. 2025

Philly's favorite toppings: Pepperoni, sausage, mushrooms, extra cheese and onions. —Isaac Avilucea, Axios, 8 Apr. 2025

Fry, stirring regularly, for 15 to 20 minutes or until pepper and onion are very tender. —Kelly Brant, Arkansas Online, 8 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