浴室
よくしつ · yokushitsu · JLPT N1 · noun
bathroom
室 — roof 宀 + arrive 至
A semantic compound: 宀 (roof/house) over 至 (to arrive). The image is a place one arrives at and stays in — an inner room. From 'inner chamber' the meaning broadened to 'room' generally, and by extension to specialized rooms like an office or laboratory.