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 any combo of meat, like shrimp, and veggies, like charred onions or mushrooms, with shredded cheese. — Malaka Gharib, NPR, 6 July 2026

This French onion pasta side dish is loaded with deep, savory flavors that our recipe testers adored. — Sarah Martens, Better Homes & Gardens, 4 July 2026

There’s a $7 sausage wrap combo with Fresnos, caramelized onions and Dijon mustard-mayo. — Bud Kennedy, Fort Worth Star-Telegram, 6 July 2026

Garlic and raw onions are largely absent from her diet, as is foie gras, which was removed from royal menus because of concerns about animal welfare. — Lizzie Lanuza, StyleCaster, 3 July 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