onesie

American  

[wuhn-zee] / ˈwʌn zi /

noun

• onesies
  plural

1. a one-piece leisure or sleeping garment for an adult, usually combining a long-sleeved top with long pants.

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Trademark.

1. Onesies, a brand name for one-piece garments for infants, the lower portion resembling briefs and having snaps across the crotch for convenience in diapering. Although a trademarked term, it is often spelled as lowercase onesie, referring to a single garment.

onesie British  

/ ˈwʌnzɪ /

noun

1. a one-piece garment combining a top with trousers, worn by adults as leisurewear

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Usage

What else does onesie mean? A onesie is a one-piece item of loungewear or sleepwear. Traditionally, onesies are worn by babies, but they exploded into adult novelty fashion in the 2010s. How is onesie pronounced?[wuhn-zee]

Other Word Forms

Noun Inflected Forms

• onesies
  plural

Etymology

Origin of onesie

First recorded in 1980–85; originally a trademark

Example Sentences

See Examples For:

onesie onesies

My mother-in-law wasn’t one for raunch; she probably just thought the onesie was silly and cute.

From Salon ● Jun. 4, 2026

An omen among omens: Mid-dog-walk that day, I spot a onesie that reads “Milk Drunk” and shudder at the impulse to recruit our newborns into low-key bacchanalia.

From Slate ● May 10, 2026

As a parent, you wouldn’t want your child to be stuck forever wearing a onesie and drinking from a sippy cup.

From The Wall Street Journal ● Jan. 1, 2026

The post included a number of family photos, including several of George in a onesie and a shot of the couple’s 2-year-old daughter Bridget checking out her new little brother.

From Los Angeles Times ● Apr. 24, 2025

Ivy laid Aaron down on the changing pad on top of the dresser and wiggled one of his arms out of his onesie.

From "Ivy Aberdeen’s Letter to the World" by Ashley Herring Blake

When guests arrived, Broussard opened gifts — onesies and diapers and bows — while Crain kept closing her eyes.

From Salon ● Nov. 1, 2024

She was one of tens of thousands of young workers in China to proudly post pictures of themselves showing up at the office in onesies, sweatpants and sandals with socks.

From New York Times ● Mar. 24, 2024

Online shops and local vendors have put together a full array of creative, limited-edition merchandise: earrings, baby onesies, ornaments, games, banners and more.

From Seattle Times ● Mar. 15, 2024

Trainee teacher Laurie Schram says she and her daughter depend on onesies and electric blankets to manage.

From BBC ● Nov. 15, 2023

She was shaking out the onesies they got from the school and checking their sizes.

From "Ivy Aberdeen’s Letter to the World" by Ashley Herring Blake