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

With tamarind, Worcestershire and plenty of onions, the sauce helps coax out the wood smoke in the meat. —Jenn Harris, Los Angeles Times, 9 June 2025

Some highlights include the Tortilla Española (traditional Spanish omelet, caramelized onions, garlic aioli) and Chicken and Waffles (buttermilk waffles topped with rosemary and more). —Amy Drew Thompson, The Orlando Sentinel, 5 June 2025

While grill is preheating, whisk together mayonnaise, sugar, orange juice, vinegar, salt, onion powder, and black pepper in a large bowl. —Josh Miller, Southern Living, 5 June 2025

Ranch: Smooth, rich and irresistibly savory – our Ranch Snack Wrap delivers a satisfying burst of cool ranch goodness, with hints of garlic and onion. —Gabe Hauari, USA Today, 4 June 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