furcula

American Heritage® Dictionary of the English Language, Fourth Edition

1. n. Zoology A forked part or bone, such as the wishbone of a bird. Also called fourchette.

Century Dictionary and Cyclopedia

1. n. In ornithology, the united pair of clavicles of a bird, forming a single forked bone, whence the name. The prongs of the furcula commonly meet at an approximately acute angle, like a V, and there develop a process called the hypoclidium; the extremities pass to each shoulder-joint. Sometimes the prongs meet at an open angle, like a U, and they may be ankylosed with the keel of the sternum. The furcula serves to keep the shoulders apart, and is strongest, with most open tines, in birds of the greatest powers of flight. It is occasionally rudimentary or defective, the clavicles being separate and very small, as occurs especially in some flightless birds. The furcula of the common fowl is familiar as the merrythought or wishbone. Also called furculum (with plural fureula).
2. n. In entomology, a forked process: specifically applied to a long bifid process on the bodies of certain caterpillars. See furciferous, 1.
3. n. 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.

Wiktionary

1. n. anatomy A forked process or structure, generally two-pronged.
2. n. ornithology The forked bone formed by the fusion of the clavicles in birds, the wishbone or merrythought.
3. n. 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.

GNU Webster's 1913

1. n. (Anat.) A forked process; the wishbone or furculum.

WordNet 3.0

1. n. a forked bone formed by the fusion of the clavicles of most birds