c. 1300, present-participle adjective from sleep (v.). Sleeping-pill is from 1660s; sleeping-bag is from 1850; sleeping sickness as a specific African tropical disease is first recorded 1875; sleeping has been used since late 14c. for diseases marked by morbid conditions. Sleeping Beauty (1729) is Perrault's La belle au bois dormant.
It is ill wakyng of a sleapyng dogge. [Heywood, 1562]
It is nought good a slepyng hound to wake. [Chaucer, c. 1385]
Old English slæpan "to be or fall asleep; be dormant or inactive" (class VII strong verb; past tense slep, past participle slæpen), from Proto-Germanic *slēpanan (source also of Old Saxon slapan, Old Frisian slepa, Middle Dutch slapen, Dutch slapen, Old High German slafen, German schlafen, Gothic slepan "to sleep"), from PIE *sleb- "to be weak, sleep," which perhaps is connected to PIE root *sleg- "be slack, be languid," the source of slack (adj.). Sleep with "do the sex act with" is in Old English:
Gif hwa fæmnan beswice unbeweddode, and hire mid slæpe ... [Laws of King Alfred, c. 900]
Related: Slept; sleeping. Sleep around is attested by 1928.
sleeping car on a passenger train, 1867, Pullman car, in recognition of U.S. inventor George M. Pullman (1831-1897) of Chicago, who designed a railroad car with folding berths.
The Pullman Sleeping Car.—"The Western World." This splendid specimen of car architecture, being one of a number of sleeping-cars to be completed for the Michigan Central road, by Mr. Pullman, has created a great sensation among railway circles east. ... The car itself is admitted by all who have seen it to be, in the matter of sleeping and cooking accessories, and superb finish, the ne plus ultra of perfection. Nothing before has been seen to equal, much less surpass it. [Western Railroad Gazette, Chicago, quoted in Appleton's Illustrated Railway and Steam Navigation Guide, New York, June, 1867]