room for boiling water; boiler room
Refers to a room or space where water is boiled, often in a traditional bathhouse or kitchen setting. Not a common modern term.
Old houses had a room for boiling water called a 湯室.
Can refer to a bathroom or bathing area, but this usage is rare and somewhat archaic. Modern Japanese typically uses 浴室 or 風呂場.
Ancient documents record that people purified themselves in the 湯室.
Compound of 湯 (hot water) and 室 (room). The exact historical derivation is uncertain, but it likely referred to a dedicated room for heating water in traditional Japanese architecture.