"lady's loose robe," 1835, from French peignoir, from Middle French peignouoir "loose, washable garment worn over the shoulders while combing the hair" (16c.), from peigner "to comb the hair," from Latin pectinare, from pecten (genitive pectinis) "a comb," related to pectere "to comb" (see fight (v.)). A gown put on while coming from the bath; misapplied in English to a woman's morning gown.
1780, extended from Icelandic Geysir, name of a specific hot spring in the valley of Haukadal, literally "the gusher," from Old Norse geysa "to gush," from Proto-Germanic *gausjan, suffixed form of PIE *gheus-, extended form of the root *gheu- "to pour." Taken by foreign writers as the generic name for spouting hot springs, for which the native Icelandic words are hverr "a cauldron," laug "a hot bath."
"very large kettle or boiler," c. 1300, caudron, from Anglo-French caudrun, Old North French cauderon (Old French chauderon "cauldron, kettle"), from augmentative of Late Latin caldaria "cooking pot" (source of Spanish calderon, Italian calderone), from Latin calidarium "hot bath," from calidus "warm, hot" (from PIE root *kele- (1) "warm"). The -l- was inserted 15c. in imitation of Latin.
Middle English shour, from Old English scur, scura "a short fall of rain, storm, tempest; fall of missiles or blows; struggle, commotion; breeze," from Proto-Germanic *skuraz (source also of Old Norse skur, Old Saxon and Old Frisian scur "fit of illness;" Old High German scur, German Schauer "shower, downpour;" Gothic skura, in skura windis "windstorm"), from PIE root *kew-(e)ro- "north, north wind" (source also of Latin caurus "northwest wind;" Old Church Slavonic severu "north, north wind;" Lithuanian šiaurus "raging, stormy," šiaurys "north wind," šiaurė "north").
By Middle English in the general sense of "a copious supply bestowed": Of blood, tears, etc., from c. 1400. Of meteors from 1835. Sense of "bath in which water is poured from above" is recorded by 1851 (short for shower-bath, itself attested from 1803). The meaning "large number of gifts bestowed on a bride" (1904, American English colloquial) later was extended to the party at which it happens (1926). Shower-curtain is attested from 1914.
"small vesicle of water or some other fluid inflated with air or gas," early 14c., perhaps from Middle Dutch bobbel (n.) and/or Middle Low German bubbeln (v.), all probably of echoic origin. Figurative use in reference to anything wanting firmness, substance, or permanence is from 1590s. Specifically in reference to inflated markets or financial schemes originally in South Sea Bubble, which originated c. 1711 and collapsed 1720. Bubble-bath recorded by 1937. Bubble-shell is from 1847.
isles off Cornwall, a name of unknown origin. Pliny has Silumnus, Silimnis. Perhaps it is connected with the Roman god Sulis (compare Aquae sulis "Bath," literally "waters of Sulis"). The -y might be Old Norse ey "island." The -c- was added 16c.-17c. "[A]bout the only certain thing that can be said is that the c of the modern spelling is not original but was added for distinction from ModE silly as this word developed in meaning from 'happy, blissful' to 'foolish.'" ["Cambridge Dictionary of English Place-Names"].
Old English læg, leag "lye, water impregnated with alkaline salt absorbed from the ashes of wood by leaching," from Proto-Germanic *laugo (source also of Middle Dutch loghe, Dutch loog, Old High German louga, German Lauge "lye"), from PIE root *leue- "to wash."
The substance formerly was used in place of soap, hence Old High German luhhen "to wash," Old Norse laug "hot bath, hot spring," Danish lørdag, Swedish lördag "Saturday," literally "washing-day," "the day appropriated by the Scandinavians to that exercise" [Century Dictionary]. Chamber-lye in early Modern English was the name for urine used as a detergent.
"ludicrous anticlimax, a descent from the sublime to the ridiculous," 1727, from Greek bathos "depth," which is related to bathys "deep" (see benthos). The word was introduced in this sense by Pope.