Pajamas, or pyjamas (British English), often shortened to PJs, jimmies, jimjams or jammies, can refer to several related types of clothing. Pajamas are loose-fitting, two-piece garments derived from the original garment and worn chiefly for sleeping, but sometimes also for lounging, also by both sexes. More generally, pajamas may refer to several garments, for both daywear and nightwear, derived from traditional pajamas and involving variations of style and material.
The word pyjama  was incorporated into the English language via the British Empire from c. 1800 through the Bengali pajāmā, itself from the Persian word pāy-jāmeh (پايجامه lit. "leg-garment"). The original pyjāmā are loose, lightweight trousers fitted with drawstring waistbands worn by Muslims in India and adopted by Europeans there.
The word pyjama was incorporated into the English language via Bengali. The word originally derives from Persian پايجامه pāyjāmeh meaning 'leg-garment'. The word originally referred to loose trousers tied around the waist.
The worldwide use of pajamas (the word and the garment) is the result of British presence in India in the 18th and 19th centuries, and British influence on the wider Western world during the Victorian era. Pajamas had been introduced to England as "lounging attire" as early as the 17th century, then known as mogul's breeches (Beaumont and Fletcher) but they soon fell out of fashion again. The word pajama (as pai jamahs, Paee-jams and variants) is recorded in English use in the first half of the 19th century, but they only become a fashion in Britain and the Western world as a sleeping attire for men in the Victorian period, from about 1870.
Hobson-Jobson: A Glossary of Colloquial Anglo-Indian Words and Phrases (1886) summarizes the state of usage at the time (s.v. "pyjammas"):
|“||Such a garment is used by various persons in India e.g. by women of various classes, by Sikh men, and most by Mohammedans of both sexes. It was adopted from the Mohammedans by Europeans as an article of dishabille and of night attire, and is synonymous with Long Drawers, Shulwaurs, and Mogul-Breeches [...] It is probable that we English took the habit like a good many others from the Portuguese. Thus Pyrard (c. 1610) says, in speaking of Goa Hospital: "Ils ont force calsons sans quoy ne couchent iamais les Portugais des Indes" [...] The word is now used in London shops. A friend furnishes the following reminiscence: "The late Mr. B—, tailor in Jermyn Street, some on 40 years ago, in reply to a question why pajamas had feet sewn on to them (as was sometimes the case with those furnished by London outfitters) answered: 'I believe, Sir, it is because of the White Ants.||”|
Traditional pajamas consist of a jacket-and-pants combination made of soft fabric, such as flannel; The jacket element usually has a placket front and its sleeves have no cuffs. For a number of reasons (increased freedom of movement, aesthetic appeal, etc.) many men opt to sleep or lounge barechested in just the pajama pants.
Some pajamas feature a drop seat (also known as a trap door or butt flap): a buttoned opening in the seat, designed to allow the wearer to conveniently use a toilet. Drop seats were very common on pajamas made before the 1950s, but today they are rather rare.
Contemporary pajamas are derived from traditional pajamas. There are many variations in style such as short sleeve pajamas, pajama bottoms of varying length, or, on occasion, one-piece pajamas, and pajamas incorporating various materials.
Chiefly in the US, stretch-knit sleep apparel with rib-knit trimmings are common. Usually worn by children, these garments often have pullover tops (if two-piece) or have zippers down the fronts (if one-piece), and may also be footed.
Pajamas may today refer to women's combination daywear, especially in the US where they became popular in the early 20th century, consisting of short-sleeved or sleeveless blouses and lightweight pants. Examples of these include capri pajamas, beach pajamas, and hostess pajamas.
Pajamas are usually loose fitting and designed for comfort, using soft materials such as cotton or the more luxurious silk or satin. Synthetic materials such as polyester and Lycra are also available.
Pajamas often contain visual references to a thing that may hold some special appeal to the wearer. Images of sports, animals, balloons, polka dots, flowers, stripes, plaids, foulards, paisleys and other motifs may all be used to decorate them. Pajamas may also be found in plainer designs, such as plaid or plain gray, but when worn in public, they are usually designed in such a way that makes their identity unambiguous. Older styles of children's pajamas have been depicted as having a square button-up flap covering the buttocks.
In January 2012, a local Dublin branch of the Government's Department of Social Protection advised that pajamas were not regarded as appropriate attire when attending the office for welfare services.
In January 2012, Michael Williams, a commissioner in Caddo Parish, Louisiana, proposed an ordinance prohibiting people from wearing pajamas in public. Caddo Parish already has a law against wearing sagging pants below the waist, but Williams is pushing for a law against pajama pants after seeing a group of young men wearing loose fitting pajama pants that were about to show their private parts. According to Williams, "The moral fiber in our community is dwindling. If not now, when? Because it's pajama pants today, next it will be underwear tomorrow.” 
Boys in stretch-knit pajamas.
Toddler in footed pajamas.
Men in white paijama with hunting cheetahs, India 1844.
Muslim woman, in Sind, British India, in salwar style pajamas, 1870.
- "'Moe' with owners James Davis & wife, in bed in children's pajamas, at home.", Life magazine, 1971, (Photographer: Ralph Crane).
- "Model clad in lounging pyjamas featuring peg-top trousers like jodpurs for sale at Neiman Marcus" Life magazine, 1939, (Photographer: Alfred Eisenstaedt)
- "Brazilian composer Heitor Villa-Lobos playing native Brazilian folk instrument from his collection, while wearing jacket over his pajamas & smoking cigarette; at home." Life magazine, 1945 (Photographer: Unknown; Location: Rio De Janeiro)
- Dictionary Meaning: Pyjama; TheFreeDictionary; Free Online Dictionary, Thesaurus, and Encyclopedia; cf. The Oxford English Dictionary. 1989 edition. Oxford University Press. Oxford and London.
- Lewis, Ivor. 1991. Sahibs, Nabobs and Boxwallahs: A Dictionary of Words of Anglo-India. Oxford: Oxford University Press. 266 pages. ISBN 0-19-564223-6. "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 (them) back ...." Encyclopedia Britannica. Retrieved December 29, 2006, from: Encyclopædia Britannica Online.
- Yule, Henry and A.C. Burnell, Hobson-Jobson: A Glossary of Colloquial Anglo-Indian Words and Phrases (1886), s.v. Pyjammas, p. 748. Hobson-Jobson glosses "white ants" as "The insect (Termes bellicosus of naturalists) not properly an ant, of whose destructive powers there are in India so many disagreeable experiences, and so many marvellous stories."
- "Girl sitting on bed and wearing striped flannel pajamas and Donald Duck slippers." Life magazine, December 1949, (Photographer: Nina Leen).
- "Millionaire Charles Ponzi posing for photograph in pajamas." Life magazine, 1942, (Photographer: Hart Preston).
- "Three college students wearing their PJs and playing in the bunk bed of their dorm room during rush week at the University of Illinois." Life magazine, September 1956 (Photographer: Grey Villet).
- "Model wearing cotton-crepe pajamas." Life magazine, 1939, (Photographer: Alfred Eisenstaedt).
- "Harriet Traynham (R) and her guests still wearing their pyjamas at 3:15 pm," Life magazine, August 1951 (Phtographer: Lisa Larsen)
- "Actress Dorothy McGuire doing morning exercises wearing silk pajamas." Life magazine, 1941, (Photographer: Alfred Eisenstaedt)
- "Cynthia Brooks standing with her mother who is making alterations on her 'baby doll' pyjamas." Life magazine, March 1957, (Photographer: Peter Stackpole).
- "Czech model posing in hostess pajamas." Life magazine, 19]9-;liop[-;pi[l;op68, (Photographer: Bill Ray)
- "Now they're shopping in pyjamas in Shanghai!" Liverpool Echo, 17 January 2009. Retrieved 1 May 2015.
- "Tesco ban on shoppers in pyjamas". BBC News. 2010-01-28. Retrieved 2013-01-23.
- "Meanwhile, In Blanchardstown". Broadsheet.ie. 2012-01-24. Retrieved 2013-01-23.
- "Louisiana Official Moves to Ban Wearing Pyjamas in Public" Courtney Subramanian. Retrieved April 15, 2012
- "Pyjamas in Public a Real Crime? | NBC 5 Dallas-Fort Worth". Nbcdfw.com. 2012-01-17. Retrieved 2013-01-23.
- "Vt. high school dress code now bans pyjamas" Retrieved on April 15, 2012
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