The Collaborative International Dictionary
Triforium \Tri*fo"ri*um\, n. [LL., fr. L. tri- (see Tri-) + foris, pl. fores, a door.] (Arch.) The gallery or open space between the vaulting and the roof of the aisles of a church, often forming a rich arcade in the interior of the church, above the nave arches and below the clearstory windows.
Wiktionary
n. The gallery of arches above the side-aisle vaulting in the nave of a church.
Wikipedia
The Triforium is the name of a six-story, 60-ton public sculpture in the Los Angeles Mall Civic Center complex, located at the intersection of Temple and Main Streets in Downtown Los Angeles.
Usage examples of "triforium".
The large triforium, small clerestory, and moderate-sized main arches give way to a large clerestory, large main arches, and practically non-existent triforium.
Thus there is nothing to mark the interior division of the main arches, clerestory, and triforium.
Above, far back in the clerestory arches, are octofoil windows with sills of over-lapping courses, which incline forward to the string course above the triforium.
All the corbels of the internal wall arcade in the triforium, between the shallow lancet windows, became as chapters in the story of his life.