rosacecommon nounSyllable DecompositionrosaceEtymologyexpandsee rose and -aceDefinitions1. A symmetrical circular ornament in the shape of a large rose, placed in the recess of a vault or ceiling.architectureexpandUn plafond orné de rosaces.2. A kind of circular clasp, more or less decorated, used to decorate the nail on which a painting is hung.techniqueexpand3. A large circular window, decorated with stained glass, in Gothic churches and cathedrals.architectureexpandOn dit plus correctement rose.Pluralrosaces