The organ gallery gets a strong white light from a row of long windows in the clerestory, which have not even coloured glass.
early 15c., probably from clere "clear," in a sense "light, lighted" (see clear (adj.)), and story (n.2), though this sense of that word is not otherwise found so early. Originally the upper part of the nave, transepts, and choir of a large church; so called because pierced with windows. Related: Clerestorial.