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

Its 16-inch pizza options include: the Pendleton Heights hot pepperoni (mozzarella, red sauce, fresh basil and olive oil) for $22 and the Northeast supreme (mozzarella, red sauce, pepperoni, sausage, mushroom, bell peppers and roasted onion) for $24. —Jenna Thompson, Kansas City Star, 22 Feb. 2025

The museum uses the garden to educate students, planting strawberries and onions, as well as weld and lady bedstraw, which are used for dyeing fabrics. —Christopher Elliott, Forbes, 22 Feb. 2025

However, experts still recommend incorporating a variety of luteolin-rich foods into your diet, such as broccoli, onions, and olive oil. —Sarah Garone, Health, 21 Feb. 2025

The colors of this dish pop, too: the red of the sauce on the pink salmon, the golden yellow potatoes, the purple red onion wedges and the curled green stems of cilantro to finish. —Mia Leimkuhler, New York Times, 20 Feb. 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

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