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

Emmanuel Haro was last seen wearing a black Nike onesie, according to authorities.

From Los Angeles Times ● Aug. 18, 2025

“You’re doing it wrong,” Layla said, snapping a onesie out of her hands.

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

She was in the store picking up formula - and some onesies and outfits for her daughter, who has yet to turn one.

From BBC ● Apr. 13, 2025

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

From Salon ● Nov. 1, 2024

I love their hanging plants and face serums named for constellations and organic onesies and astrology soaps and beautiful, teeny-tiny, cork-stoppered glass bottles filled with colorful matches, retailing for $16.

From Seattle Times ● Mar. 27, 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

Layla gripped the baby bag, onesies and diapers overflowing.

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