Medieval Latin a gallery in Canterbury Cathedral (later taken to mean “with three openings”)
American Heritage Dictionary of the English Language, 5th Edition
Triforium Sentence Examples
The top of the narthex forms a wide gallery, communicating with the interior at the triforium level.
"Gynaeconitis" is the term given by Procopius to the space reserved for women in the Eastern Church, and this separation of the sexes was maintained in the early Christian churches where there were separate entrances and accommodation for the men and women, the latter being placed in the triforium gallery, or, in its absence, either on one side of the church, the men being on the other, or occasionally in the aisles, the nave being occupied by the men.
The original triforium is transformed into a clerestory, the original clerestory being lost.