Another etymology traces it through the obsolete noun lungis "slow, lazy person" (c. 1560), which is from French longis "an idle, stupid dreamer," a special application, for some obscure reason, in Old French of the proper name Longis, which is from Latin Longius, Longinus. In old mystery plays and apocryphal gospels, Longinus is the name of the centurion who pierces Christ's side with a spear; the name perhaps was suggested by Greek longe "a lance" in John xix.34. But popular etymology associated the name directly with long (adj.). Related: Lounged; lounging; lounger.
1701, "pleasure carriage," from French chaise "chair" (15c.), dialectal variant of chaire (see chair (n.)) due to 15c.-16c. Parisian accent swapping of -r- and -s-, a habit often satirized by French writers. French chair and chaise then took respectively the senses of "high seat, throne, pulpit" and "chair, seat," but this was after chair had been borrowed into English in the older sense.
Originally a one-horse, two-wheeled carriage for two persons, later extended to other types of pleasure or travelling carriages. Chaise lounge (1800) is corruption of French chaise longue "long chair," the second word confused in English with lounge.
Altered in French by influence of lit "bed." The meaning was extended early 15c. to "straw used for bedding" (this sense is early 14c. in Anglo-French) and by late 15c. to "offspring of an animal at one birth" (that is, in one bed). Litter by 19c. had come to mean both the straw bedding and the animal waste in it after use. The sense of "scattered oddments, disorderly debris" is first attested 1730 and probably is from litter (v.) "provide with bedding" (late 14c.) and sense extended from the image of strewing straw.