onesie

noun

one·​sie ˈwən-zē 

plural onesies

1

: a bodysuit for an infant having a snap closure at the crotch and not covering the legs

… her husband, Prince William, gratefully accepted a onesie labeled "Daddy's Little Co-Pilot" from a well-wisher …

—Michelle Tauber et al.

2

: a one-piece garment for adults usually with long sleeves and pants and sometimes with a hood

… pole-vaulter Holly Bradshaw wore a onesie rather than a crop top and bikini to win her bronze …

—Vanessa Friedman

Examples of onesie in a Sentence

Recent Examples on the Web

Tayler posted a photo of the newborn baby in a sweater onesie, as well as photos of all four family members holding Sutton in their arms. —Charna Flam, PEOPLE, 25 Nov. 2025

The boy is wearing a white Christmas pajama onesie with Christmas trees and bells on it. —Jessica Van Egeren, jsonline.com, 21 Nov. 2025

There are also layering pieces, including full-length leggings, long-sleeve tops and shine onesies, with the upper apparel featuring thumb holes in the sleeves for functionality, comfort and layering opportunities. —Jaden Thompson, Footwear News, 20 Nov. 2025

By the end of the day, the Post was selling baby onesies and commemorative plates emblazoned with the cover. —David Bauder, Fortune, 19 Nov. 2025

Word History

Etymology

one entry 1 + -sie (after the trademark Onesies)

First Known Use

1983, in the meaning defined at sense 1

Rhymes for onesie

• breezy
• cheesy
• easy
• queasy
• sleazy
• wheezy
• marchese
• speakeasy
• uneasy