penthouse
n//ˈpɛnt(h)aʊs//takvåning, vindsvåning
(now, historical) A structure or annexe (especially one with a sloping roof) extending from the side of a building, sometimes as protection from the weather. [from 14th c.]
An apartment or suite found on an upper floor, or floors, of a tall building, especially one that is expensive or luxurious with panoramic views. [from 19th c.]