triforium definition by Webster's New World
Webster's New World College Dictionary Copyright © 2010 by Wiley Publishing, Inc., Cleveland, Ohio. Used by arrangement with John Wiley & Sons, Inc.
noun pl. triforia
a gallery or arcade in the wall above the arches of the nave, choir, or transept of a church
Origin: Midieval Latin ; from Classical Latin tri-, tri- plush foris, door
triforium definition by American Heritage Dictionary
noun pl. tri·fo·ri·a Architecture
A gallery of arches above the side-aisle vaulting in the nave of a church.
Origin: Medieval Latin, a gallery in Canterbury Cathedral (later taken to mean “with three openings”).