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 addition of spoken word passages by local Geordie poet Cooper Robson, who drifts through balladic descriptions of community, working-class masculinity, and pickled onions, aids Knats in their explorations of their hometown. —Archie Forde, Pitchfork, 1 May 2026

Strips of beef are cooked in a screaming hot wok with cherry tomatoes, onion and French fries, then seasoned with soy sauce and black pepper. —Jenn Harris, Los Angeles Times, 30 Apr. 2026

Enjoy dishes such as Melon Con Jamon with watermelon, Roma tomatoes, crispy Serrano, truffle honey and goat cheese or the Bulla Burger featuring piquillo peppers, caramelized onions, Tetilla and smoked paprika fries. —Amy Drew Thompson, The Orlando Sentinel, 30 Apr. 2026

Mamlets are cooked in pungent mustard oil and amped up with onions and chiles. —Madhushree Basu Roy, Saveur, 30 Apr. 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