Child's one-pieces are a type of clothing typically worn by infants and toddlers. They are usually made of soft, comfortable fabric and consist of a single piece that covers the torso and legs. The most common type of one-piece is known as a romper, which is a garment with short or long legs and sleeves, and usually fastens at the crotch. Rompers are often brightly colored and decorated with patterns or characters, making them popular among young children.