・ 音 カイ
Sino-Vietnamese: giai
阝(mound, slope) for meaning, 皆 (all, alike) for sound: evenly spaced steps cut into a hillside. A stair, a storey, a rank.
Stroke data: KanjiVG (CC BY-SA 3.0) — kanjivg.tagaini.net
事務所は三階にあります。 (じむしょはさんがいにあります)
The office is on the third floor.