n A tuft, or other excrescence or natural ornament, growing on an animal's head; the comb of a cock; the swelling on the head of a serpent; the lengthened feathers of the crown or nape of bird, etc.
n The plume of feathers, or other decoration, worn on or displayed on a helmet; the distinctive ornament of a helmet.
n (heraldry): A bearing worn, not upon the shield, but usually on a helmet above it, sometimes (as for clerics) separately above the shield or separately as a mark for plate, in letterheads, and the like.