Main Page | See live article | Alphabetical index In architecture, a penthouse is a building on the roof of another building, or alternatively, an apartment on the top floor of a building. See penthouse apartment. Penthouse apartments are often expensive, and associated with a luxury lifestyle: this connotation was presumably the inspiration for the title of the pornographic magazine Penthouse. This article is from Wikipedia. All text is available under the terms of the GNU Free Documentation License.