triforium
/traɪˈfɔriəm/
noun
- A gallery or arcade above the arches of a church nave, often with three openings per bay.
- The architect designed a triforium to let more light into the upper part of the church.
- Visitors can walk through the triforium to see the stained glass windows up close.
- The cathedral's triforium was decorated with intricate stone carvings.