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

To make the marinade, to a blender, add the chiles, garlic, onion, ginger, lime juice, chili powder, salt, and turmeric and blend into a smooth paste with no chunks. — Emma Specter, Vogue, 14 Oct. 2026

Place onion, apple, lemon quarters, and herb sprigs inside cavity. — Sarah Martens, Better Homes & Gardens, 14 Oct. 2026

Traditional liners add warmth without the bulk of a heavier coat, and many feature the distinctive curved stitching known as onion quilting, a detail that still shows up in current outerwear. — Ashley Lynch, Fort Worth Star-Telegram, 14 Oct. 2026

Lightweight quilting, often in the curved pattern known as onion quilting, delivers warmth without the weight of a full coat. — Ashley Lynch, Miami Herald, 14 Oct. 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
• French onion soup
• green onion
• onion dome
• onion ring
• onion soup
• 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