köken: Originally "remote place", at first in Middle Low German afort (16th century). The contemporary sense as a euphemism since the 18th century. Analysable as ab (“off, away”) + Ort (“place”).
So etwas habe ich seit Jahrzehnten nicht mehr erlebt. Finstere Halle, Türkenklo, streng riechend wie schwäbische Aborte vor fünfzig Jahren.
köken: Inherited from Old Spanish banno, from Latin baneum, variant of balneum.
aile: baño de arena, baño de asiento, baño de bosque, baño de María, baño de masas, baño de multitudes, baño de sangre, baño maría, baño turco, bata de baño
Example: "Alfajores con baño de chocolate cobertura" or "con baño azucarado" refer to confections covered with a chocolate or sugar glaze.
köken: Learned borrowing from Katharevousa ἀποχωρητήριον (apochoritírion) (first attested in 1888), from the past stem αποχωρη- (apochori-) of αποχωρώ (apochoró, “to withdraw, pull out”) + -τήριο (-tírio, “place suffix”).
köken: First attested in the Worin seokbo (月印釋譜 / 월인석보), 1459, as Middle Korean 뒷〯간 (Yale: twǔy-s-kàn). 뒤 (dwi, “back”) + -ㅅ- (-s-) + 간(間) (gan, “room”).
köken: From English (water) closet, via French (water-)closet and semi-calque German (Wasser)Klosett.
Etimoloji
Appears to be a coinage in Japanese from Middle Chinese-derived roots, as a compound of 便 (ben, “convenience, ease”, also meaning “bodily waste; bowel movement”) + 所 (sho, “place”). The sho changes to jo as an instance of rendaku (連濁). Compare English expressions seat of ease, house of ease, also pooper, shitter. First cited in works from the late 1400s.