noun
sloping ceiling; slanted ceiling
Architectural term for a ceiling that is not horizontal but inclined, often found in attics, under roofs, or in modern design.
この部屋は勾配天井になっていて、開放感がある。
This room has a sloping ceiling, which gives it a sense of openness.
勾配天井の断熱工事を検討している。
We are considering insulation work for the sloping ceiling.
Compound of 勾配 (こうばい, 'slope, incline') and 天井 (てんじょう, 'ceiling'). The exact historical derivation is uncertain, but the term is straightforwardly descriptive.