rose window
From Longman Dictionary of Contemporary Englishrose windowˌrose ˈwindow noun [countable] a circular window in a church, especially one with coloured glass in itExamples from the Corpusrose window• The patterns show every lace doily, rose window or Persian carpet you can imagine.• The western porch below, surmounted by its rose window, is sculptured.• Above: Chartres Cathedral: north rose window and west rose window.• At the top a small rose window afforded some light.