Triforium is an architectural term for a gallery or arcade situated above the arches of the nave, choir, or transept of a church. It is also known as a tribune or a gallery. Synonyms for triforium include clerestory, balcony, mezzanine, and upper gallery. The clerestory is an elevated section of a wall containing windows that allow natural light to enter the building. A balcony is a platform projecting from the wall of a building, while a mezzanine is an intermediate floor between the main floors of a building. An upper gallery, like a triforium, is an elevated section within a building, usually supported by columns or arches.