Chancel, Clerestory

Chancel: This is the area around the altar in a church, possibly containing a space for the choir and separated by a screen.

Clerestory: (Pronounced "clear story") While this was original the upper level of a church, Frank Lloyd Wright used the term to describe a row of windows at the peak of the roof.

The skinniest turret was a spiral stair that led up to the triforium, which was a sort of a raised gallery that ran all the way around the inside of the chancel above the screens and below the soaring clerestory windows.