n. In anatomy, a protuberance on the end of a bone serving to form an articulation with another bone: more especially applied to the prominences of the occipital bone for articulation with the atlas, to the prominences at the distal extremity of the humerus and femur respectively, and to the proximal articular extremity of the lower jawbone of mammals.n. In the arthropod or articulated animals, a rounded portion of the hard integument fitting into another part to which it is articulated, as the proximal ends of the tibiæ in insects.n. An ancient Greek long measure, the eighth of a foot. See foot.