What is the name of the large circular window often found on the west façade? It is called a rose window.
A rose window is a large circular window divided by radiating stone tracery into sections resembling petals or spokes. It is especially associated with Gothic architecture, where it could occupy a major position above the western entrance or in the transepts. Filled with stained glass, the window admitted coloured light while providing a dramatic visual focus.
The form developed from earlier “wheel windows” and became increasingly elaborate as Gothic builders refined tracery. Medieval designers used geometry to organize the radiating pattern, sometimes arranging figures, symbols, or scenes in rings around the centre. The best-known examples include the rose windows of Notre-Dame de Paris and Chartres Cathedral.
“Rose window” describes the architectural form, not the material alone: a rose window may contain stained glass, but the terms are not interchangeable. An oculus is also circular, usually simpler and smaller, while a clerestory is a high band of windows and a lancet window is tall and narrow.