UROPYGIUM

uropygium

(noun) posterior part of a bird’s body from which the tail feathers grow

Source: WordNet® 3.1

Etymology

Noun

uropygium (plural uropygia)

The posterior part of a bird's body from which the tailfeathers grow.

Source: Wiktionary

U`ro*pyg"i*um, n. Etym: [NL., fr. Gr. (Anat.)

Definition: The prominence at the posterior extremity of a bird's body, which supports the feathers of the tail; the rump; -- sometimes called pope's nose.

Source: Webster’s Unabridged Dictionary 1913 Edition