a grand or flamboyant manner; verve; style; flair: The actor who would play Cyrano must have panache.
2.
an ornamental plume of feathers, tassels, or the like, especially one worn on a helmet or cap.
3.
Architecture. the surface of a pendentive.
Origin: 1545–55; variant (after F) of pennache < Middle French < early Italianpennachio < Late Latinpinnāculum, diminutive of pinna wing; identical in form with pinnāculumpinnacle
1553, "a tuft or plume of feathers," from M.Fr. pennache "tuft of feathers," from It. pennaccio, from L.L. pinnaculum "small wing, gable, peak" (see pinnacle). Fig. sense of "display, swagger" first recorded 1898 (in translation of "Cyrano de Bergerac"), from French.