1911 Encyclopædia Britannica/Spire Light

SPIRE LIGHT (Fr. lucarne), the term given to the windows in a spire which are found in all periods of English Gothic architecture, and in French spires form a very important feature in the composition. There is an early example in the spire of the cathedral at Oxford; they are not glazed, and have occasionally, if of large size, transoms to strengthen the mullions.