upstairsˈ adverb

1. In or toward a higher storey, or (figurative) position
2. In the head, mentally (informal)

1. The part of a building above the ground floor
2. (esp formerly) the upper part of a house, as opposed to the servants' quarters in the basement
3. Its occupants, usu the householder and family

(also upˈstair) of or in an upper storey or flat