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

All eyes were on Pharrell Williams' wife, Helen Lasichanh, during the Met Gala on May 1, but it was for all the wrong reasons. We were hoping Helen would show off her amazing post-baby body after birthing triplets, but instead, she covered her body in a giant red onesie that some Twitter users were comparing to the red Teletubbie!

—Christopher Rogers

Examples of onesie in a Sentence

Recent Examples on the Web

The baby was seen in a blue onesie. —Jason Pham, StyleCaster, 22 Oct. 2025

Dunkin’s Halloween merchandise takes clear inspiration from the baked good with a costume onesie, pillows, hats and more swag decorated with the doughnut. —Sabrina Weiss, PEOPLE, 22 Oct. 2025

Fans of the Dunkin' Spider Donut can also level up their fandom with new merchandise, from plushies to onesies. —Sophia Beams, Better Homes & Gardens, 17 Oct. 2025

In a Facebook post filled with photos showing off some pittie onesies, the shelter announced she was getting adopted that day. —Tj MacIas, Kansas City Star, 14 Oct. 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