What is an Infant Snapsuit?

A snapsuit, otherwise known as a onezie, bodysuit or one-piece is 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. Snapsuits are beneficial to the wearer and caregiver alike because they offer support to help keep the diaper in place.

Source: Wikipedia, the free encyclopedia.