onesie

plural onesies

1. Any of various one-piece attires:
   1. USA one-piece garment for an infant or small child, generally worn over a diaper.

      The Fever shared a video of the meeting on X (formerly known as Twitter), where an excited Clark got to hold the young baby and sign the youngster's onesie.

      2024 August 16, Natasha Dye, “Caitlin Clark Signs Indiana Fever Fan's 2-Week-Old Baby: 'So Cute'”, in People

      1 more example

      It was once considered taboo to even suggest that new motherhood was not all sunshine onesies and rainbow mobiles, and “Baby Ruby” arrives on a welcome wave of contemporary movies exploring how the joys of child rearing can commingle with misery.

      2023 February 2, Natalia Winkelman, “‘Baby Ruby’ Review: Enfant Terrible”, in The New York Times

      Synonyms: diaper shirt, romper, romper suit

   2. A one-piece adult loungewear jumpsuit.
   3. A one-piece fashionable streetwear worn mostly by teenagers.