► 名詞
階 [(1)かい] meaning: floor rank: 2
☆ 彼の部屋は上の階だ ⇨ His room is on the floor above (☛ The concept of 階 is actually a level or strata, not a floor, so 一階 is the ground floor, 二階 is 1st floor in the European convention)
☆ 私の部屋は十階にある ⇨ My room is on 10th floor (☛ The concept of 階 is actually a level or strata, not a floor, so 一階 is the ground floor, 二階 is 1st floor in the European convention)
More examples:
- うちのカレーには三段階の辛さがあります ⇨ Our curries come in three levels of spiciness
 - 彼は同じ建物の二階から五階に転居した ⇨ He moved from a room on 2nd to 5th floors in the same building
 - 彼は三階から落ちたが軽傷を負っただけだった ⇨ He fell from the third floor but suffered only minor injuries
 - 改革は段階を追って行われる ⇨ The restructuring will be done step by step, in multiple phases
 - 彼等はウランを兵器段階まで濃縮することに成功した ⇨ They have succeeded to enrich uranium to the weapon grade
 - 私は階段を降りた ⇨ I walked down the stairs
 - 上の階の足音がうるさい ⇨ The footsteps from the floor above are loud
 - 階級闘争 ⇨ Class conflict
 - 下の階は商店だ ⇨ The floor below is a store
 - 新システムを段階的に導入する予定です ⇨ We plan to introduce the new system in stages, gradually
 - 軍隊の階級 ⇨ Military ranks
 - 彼は三階級の王座を手中にした ⇨ He has won championships in three weight classes
 - 建物の最上階 ⇨ The highest story of the building
 - 彼は階段を転げ落ちた ⇨ He tumbled down the stairs
 - 彼は膝が悪くて階段が登れない ⇨ He cannot walk up stairs because of bad knees