n. In ornithology, the united pair of clavicles of a bird, forming a single forked bone, whence the name.n. In entomology, a forked process: specifically applied to a long bifid process on the bodies of certain caterpillars. See furciferous, 1.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.