Pajamas are the comfortable, loose-fitting clothes people wear to bed. They usually come in two pieces: a soft shirt and matching pants, though some pajamas are one-piece suits that zip or button up the front. The word comes from Persian and Hindi, where similar loose pants were everyday clothing in hot climates.

In America, kids often call them PJs for short. You might have flannel pajamas covered with patterns for winter, or thin cotton ones for summer. Some people prefer nightgowns instead, while others just wear an old T-shirt and shorts to sleep.

The word also appears in fun phrases. A pajama party (or slumber party) is when friends sleep over at someone's house, staying up late in their pajamas. Some schools hold pajama days where everyone wears their pajamas to class as a special treat.

Wearing pajamas signals that you're ready to wind down and rest. When someone's working from home in their pajamas all day, it can suggest they never quite got around to starting their day properly. Fresh, clean pajamas after a bath can be one of the best feelings at the end of a long day.