Plume  —n. 1 feather, esp. A large one used for ornament. 2 ornament of feathers etc. Worn on a helmet or hat or in the hair. 3 something resembling this (plume of smoke). —v. (-ming) 1 decorate or provide with a plume or plumes. 2 refl. (foll. By on, upon) pride (oneself on esp. Something trivial). 3 (of a bird) preen (itself or its feathers). [latin pluma]