Sleepwear is clothing designed specifically for sleeping. The most common types are pajamas (a matching shirt and pants set), nightgowns (a loose dress), and nightshirts (an oversized shirt worn alone). People choose sleepwear that's comfortable and loose enough to move freely while they sleep.

Different cultures have different sleepwear traditions. In Japan, people often wear loose cotton robes called yukata. In many Western countries, children wear one-piece pajamas with feet, sometimes called “footie pajamas” or “footed pajamas.” Some people prefer to sleep in just a T-shirt and shorts, while others like fancy silk pajamas.

Sleepwear is also called nightwear or nightclothes. Before the 1900s, most people slept in long nightgowns or nightshirts made of cotton or linen. Modern sleepwear comes in countless styles and fabrics, from cozy flannel for winter to light cotton for summer. Whatever you wear to bed, whether it's special pajamas or just comfortable old clothes, counts as your sleepwear.