caliper

callus 1 A localized, firm thickening of the superficial layer of skin as a result of repetitive friction. A callus on the skin of the foot may have become thick and hard from rubbing against an ill-fitting shoe. Calluses of the feet may lead to other problems, such as serious infections. Shoes that fit well can keep calluses from forming on the feet. Also known as keratoma. 2 Hard new bone substance that forms in an area of a bone fracture. It is part of the natural process of bone repair.