uropygium/jʊəɹəˈpɪd͡ʒɪəm/EtymologyMediaeval Latin, from Ancient Greek οὐροπύγιον (ouropúgion, “tail feathers”).uropygium means the posterior part of a bird's body from which the tailfeathers grow. Lexicurio rates it Sui generis — a strength score of 88 out of 100.nounThe posterior part of a bird's body from which the tailfeathers grow.