Spire light the term given to the windows in a spire

Spire

A spire is a tapering conical or pyramidal structure on the top of a building, particularly a church tower. Etymologically, the word is derived from the Old English word spir, meaning a sprout, shoot, or stalk of grass....

 which are found in all periods of English Gothic architecture

Gothic architecture

Gothic architecture is a style of architecture that flourished during the high and late medieval period. It evolved from Romanesque architecture and was succeeded by Renaissance 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

Transom (architectural)

In architecture, a transom is the term given to a transverse beam or bar in a frame, or to the crosspiece separating a door or the like from a window or fanlight above it. Transom is also the customary U.S. word used for a transom light, the window over this crosspiece...

 to strengthen the mullion

Mullion

A mullion is a vertical structural element which divides adjacent window units. The primary purpose of the mullion is as a structural support to an arch or lintel above the window opening. Its secondary purpose may be as a rigid support to the glazing of the window...

s.

The term lucarne is used in France to mean "dormer window". They take many different forms which distinguishes the form of small roof above the window. "à chevalet" (straight lucarne), lucarne avec saillie and lucarne "à la capucine" (or with receding roof).