noun
penthouse
PENT-house/ˈpenthaʊs/
A luxury apartment on the top floor of a building.
The penthouse occupies the top floor and opens onto a private terrace.

Etymology
The ancestral word meant an attached building, such as a shed with a projecting roof. Its later use for a dwelling built on a building's roof brought the modern association with luxury.
In context
The building consists of seven full-floor residences, which have all been sold, except for the penthouse that we'll be touring today. Now, let's take a look inside. Here we are at the landing on the top floor.
More examples
- They toured a penthouse with a private terrace.
- The elevator opened directly into the penthouse.
- The building's top floor contained two penthouses.
Forms
penthouse · penthouses
Similar words
- apartment
- The broad dwelling category without the rooftop or luxury implication.