noun, plural pent·hous·es [pent-hou-ziz] /ˈpɛntˌhaʊ zɪz/.
Origin of penthouse
Word Origin for penthouse
pendize, early 14c., from Anglo-French pentiz, a shortening of Old French apentis "attached building, appendage," from Medieval Latin appendicium, from Latin appendere "to hang" (see append). Modern spelling is from c.1530, by folk etymology influence of Middle French pente "slope," and English house (the meaning at that time was "attached building with a sloping roof or awning"). Originally a simple structure (Middle English homilies describe Jesus' birthplace in the manger as a "penthouse"); meaning "apartment or small house built on the roof of a skyscraper" first recorded 1921, from which time dates its association with luxury.