ὀρροπύγιον · orropygion — LSJ
rump of birds, in which the tail-feathers are set, Arist. HA 504a32, 618b33, al. (with vv. ll. οὐροπ-, ὀροπ-, cf. τοὐροπ- in Phld. Rh. 2.189 S., but ὀρροπ- is certain in IG 2(2).1498.27 (Athens, iv B. C.)); of the sepia, Arist. HA 525a12 : generally, tail, rump of any animal, Ar. V. 1075, Nu. 162.