Meaning

noun the light horny waterproof structure forming the external covering of birds

originFrom Late Middle English plumage, plummage (“bird’s feathers collectively, plumage; (falconry) feathers fed to a hawk to cause it to regurgitate, casting”), from Middle French plumage, plomage (“bird’s feathers collectively; person’s (showy) clothing”), from Old French plumage (“bird’s feathers collectively”) (modern French plumage), from plume (“feather, plume”) + -age (suffix forming nouns…

Etymology from Wiktionary, CC BY-SA 3.0