A nightgown is a loose, comfortable dress worn for sleeping. Unlike pajamas, which come as separate tops and bottoms, a nightgown is a single garment that hangs from the shoulders down to somewhere between the knees and ankles.

Nightgowns are designed to be easy to move around in while you sleep. They're usually made from soft fabrics like cotton or flannel. Some are simple and plain, while others might have buttons, lace, or patterns. In colder weather, people often choose thick flannel nightgowns to stay warm, while summer nightgowns are lighter and more breathable.

Nightgowns have been worn for hundreds of years, though they look quite different now than they did in earlier times, when people wore much more elaborate sleepwear.

You might also hear nightgowns called nighties (a casual, affectionate nickname) or nightdresses. Some people prefer nightgowns to pajamas because there's nothing tight around the waist, while others find pajamas more practical for moving around the house in the morning.