The word “pyjama” was incorporated into English from the Hindustani language. The word originally derives from the Persian word پايجامه Payjama meaning “leg garment.”

The worldwide use of pyjamas, both the word and the garment, is the result of British presence in South Asia in the 18th and 19th centuries. According to Yule and Burnell’s Hobson-Jobson (1903)the word originally referred to loose trousers tied around the waist.

Such a garment is used by various persons in India e.g. by women of various classes, by Sikh men, and most by Muslim of both sexes. It was adopted from the Muslim by Europeans as an article of dishabille and of night attire … 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 40 years ago, in reply to a question why pyjammas 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.”

Examples. 1828: “His chief joy smoking a cigar in loose Paee-jams and native slippers.” Orient. Sport. Mag. reprint 1873, i. 64. 1881: “The rest of our attire consisted of that particularly light and airy white flannel garment, known throughout India as a pyjama suit.” Haekel, Ceylon, p. 329.

According to Encyclopaedia Britannica, “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 ….”

Over the past few decades pyjamas have become less popular and many younger men now sleep in their underwear or naked.