A onesie is a one-piece garment that typically covers the torso and often extends to the legs. Originally designed for infants, onesies are made from soft, comfortable materials like cotton and are easy to put on and take off. They often feature snap closures at the bottom for quick diaper changes, making them practical for parents. In recent years, onesies have gained popularity among adults as loungewear or sleepwear. These adult versions often come in fun designs, including animal shapes or cartoon characters, and are sometimes referred to as adult onesies or kigurumi. They provide warmth and comfort, making them a favorite for cozy nights in.