furcula

from The American Heritage® Dictionary of the English Language, 5th Edition.

• noun A forked part or bone, such as the wishbone of a bird.

from The Century Dictionary.

• noun In ornithology, the united pair of clavicles of a bird, forming a single forked bone, whence the name.
• noun In entomology, a forked process: specifically applied to a long bifid process on the bodies of certain caterpillars. See furciferous, 1.
• noun In embryology, a forked median protuberance arising in the floor of the embryonic pharynx between the third and fourth pairs of visceral arches. It develops into the epiglottis of the adult.

from the GNU version of the Collaborative International Dictionary of English.

• noun (Anat.) A forked process; the wishbone or furculum.

from Wiktionary, Creative Commons Attribution/Share-Alike License.

• noun anatomy A forked process or structure, generally two-pronged.
• noun ornithology The forked bone formed by the fusion of the clavicles in birds, the wishbone or merrythought.
• noun entomology The (two-pronged,) forked, somewhat tail-like organ held bent forward and secured by a catch beneath most species of Collembola (springtails), with which they jump by releasing the catch abruptly when alarmed.

from WordNet 3.0 Copyright 2006 by Princeton University. All rights reserved.

• noun a forked bone formed by the fusion of the clavicles of most birds