What defines a "penthouse" in relation to property?

A penthouse is typically defined as a luxury apartment situated on the top floor of a residential building. This designation comes with the implication of exclusivity and high-end features, such as expansive views, private outdoor space, and premium finishes. The top-floor location often provides greater privacy and can offer amenities that distinguish it from other units in the building.

The characteristics that set a penthouse apart from other types of apartments involve its elevated position and the associated luxury often expected in such a unit. Consequently, the choice that identifies a penthouse as a luxury apartment on the building's top floor aligns perfectly with the established definition and common understanding of this term in real estate.