also: さんかい
noun
third floor; third storey
Refers to the third floor of a building. In Japanese floor counting, the ground floor is 一階 (いっかい), so 三階 is two floors above ground level.
デパートの三階にはおもちゃ売り場があります。
The toy department is on the third floor of the department store.
このビルは三階建てです。
This building is three storeys tall.
Compound of 三 (san, 'three') and 階 (kai, 'floor, storey'). The reading がい is a result of rendaku (sequential voicing).