[ wuhn-zee ]

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

  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.

Origin of onesie

First recorded in 1980–85; originally a trademark

Words Nearby onesie Unabridged Based on the Random House Unabridged Dictionary, © Random House, Inc. 2024

How to use onesie in a sentence

British Dictionary definitions for onesie


/ (ˈwʌnzɪ) /

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

Collins English Dictionary - Complete & Unabridged 2012 Digital Edition © William Collins Sons & Co. Ltd. 1979, 1986 © HarperCollins Publishers 1998, 2000, 2003, 2005, 2006, 2007, 2009, 2012