'Must Know'
Structural Features of a
Gothic Cathedral:

• Ambulatory : A continuous isle which wraps a circular structure or an apse at its base. Designed for use in Processions.
  
  
• Apse : Particular to the East end of Cathedrals, the Apse is a semicircular form serving as a culmination. The Apse, generally domed, will often form the Altar. The term is derived from the Medieval Latin: absis or apsis.
  
  
• Choir : The section of a Cruciform Cathedral located between the Nave and the main Altar. But be careful! The exact perimeter of the Choir is often disputable from cathedral to cathedral. By definition: the place where the psalms are sung. Loosely used to define the whole East end of a cathedral, and as a synonym for Chancel.
  
  
• Flying Buttress : A masonry support branching from the sturdy piers and vertical Standing buttresses. Their role is to transfer the great weight of the vaulted roofs off to this more solid support of the firmly set abutments. In French: "arc boutant."
  
  
• Lady Chapel : If you are considering taking on some part time work in one of the Notre Dames, you had better memorize this term. The Lady Chapel will be found in all the Notre Dames, as well as many of the Great Gothic Cathedrals. Usually located behind the Sanctuary, these spaces are dedicated to - sometimes set aside for the use of - the Blessed Virgin.
  
  
• Pier : Without piers there would be no Great Cathedrals to speak of. The solid standing piers serve as the main support to the heavy strain of the Gothics vertical aspirations. The piers take on many column shapes (rounded, cross and rectangular) but will also take the form of a segment of wall. The term derives from the Norman French: piere or pere.
  
  
• Rose Window : Arguably one of the finest developments in the history of Western art. Evolving from the simple round windows of the Romanesque period these intricate works of glass, metal and stone literally flowered into holistic representations of the known Universe. While glass windows were used in cathedrals of other countries, the Rose Window was initially a French creation, first appearing at St-Denis.
  
  
• Sexpartite Vault : Essentially a four part (Quadripartite) vault to which an additional transverse rib has been incorporated which divides the vault into six segments. This is yet another form which remained distinct to the Gothic period.
  
  
• Tracery : Located throughout Gothic cathedrals, tracery adds much to the distinctive style of Gothic ornament. The variety of Tracery patterns within these cathedrals is nearly endless. Their interlacing lines are incorporated into vaults, walls, columns, windows and the woodwork of the screens.
  
         Great edifices, like the great mountains, are the work of ages. Often art undergoes a transformation while they are waiting pending completion—pendent opera interrupta—they then proceed imperturbably in conformity with the new order of things. The new art takes possession of the monument at the point at which it finds it, absorbs itself into it, develops it after its own idea, and completes it if it can. The matter is accomplished without disturbance, without effort, without reaction, in obedience to an undeviating, peaceful law of nature—a shoot is grafted on, the sap circulates, a fresh vegetation is in progress. Truly, there is matter for mighty volumes; often, indeed, for a universal history of mankind, in these successive layers of different periods of art, on different levels of the same edifice. The man, the artist, the individual, are lost sight of in these massive piles that have no record of authorship; they are an epitome, a totalization of human intelligence. Time is the architect—a nation is the builder.
  
  —Victor M. Hugo, Notre Dame de Paris