[trahy-fawr-ee-uh
m, -fohr-] 
[-fawr-ee-uh, -fohr-] . Architecture. | (in a church) the wall at the side of the nave, choir, or transept, corresponding to the space between the vaulting or ceiling and the roof of an aisle, often having a blind arcade or an opening in a gallery. |
| tri·fo·ri·um (trī-fôr'ē-əm, -fōr'-) n. pl. tri·fo·ri·a (-fôr'ē-ə, -fōr'-) Architecture A gallery of arches above the side-aisle vaulting in the nave of a church. [Medieval Latin, a gallery in Canterbury Cathedral (later taken to mean "with three openings").] |
triforium
in architecture, space in a church above the nave arcade, below the clerestory, and extending over the vaults, or ceilings, of the side aisles. The term is sometimes applied to any second-floor gallery opening onto a higher nave by means of arcades or colonnades, like the galleries in many ancient Roman basilicas or Byzantine churches. The triforium became an integral part of church design during the Romanesque period, serving to light and ventilate the roof space. With the development of the Gothic vaulting system in France, the triforium diminished in size and importance. The cathedrals at Reims (begun 1211) and Amiens (1220-47) both have triforia of little relative height but with rich arcading.
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