Infant bodysuit

Onesie or onesize is American English for a bodysuit designed to conceal a diaper when worn. This one-piece garment is sometimes also referred to as a creeper or diaper shirt. The shirt extends past the waist and has snaps or buttons that allow it to be closed over the crotch, with enough extra room to accommodate a diaper. Onesies are beneficial to the wearer and caregiver alike because they offer support to help keep the diaper in place. Onesies also are sometimes made so that the shirting material extends down the thigh about half-way to the knees, with snaps along the crotch to allow for the diaper to be changed without removing the garment completely. Worn commonly by very small children, incontinent persons, and infantilists.

Even though the word onesie is commonly used for this kind of garment it is in fact a registered trademark of Gerber Childrenswear, Inc..

See also