loose, lightweight trousers first worn in the East, or a loose two-piece suit consisting of trousers and a shirt, made of silk, cotton, or synthetic material and worn for sleeping or lounging.

They were introduced in England as lounging attire in the 17th century but soon went out of fashion. About 1870 they reappeared in the Western world as sleeping attire for men, after returning British colonials brought back with them the pajamas worn by Hindus. At the beginning of the 20th century, pajamas were introduced as women's sleepwear and about 1920 as at-home evening wear.