penthouse, pendice, pentice
1. A structure occupying usually less than half the roof area of a flat-roofed building, and used: (a) to house equipment for elevator, ventilation or air conditioning, or other mechanical or electrical systems serving the building, or (b) to house one or more apartments, access to which is gained by a stair or stairs, or a separate elevator but usually not by the building’s main elevators.
2. An appentice.
McGraw-Hill Dictionary of Architecture and Construction. Copyright © 2003 by McGraw-Hill Companies, Inc.