callus /kal″əs/ [L, hard skin] , 1. a common, usually painless thickening of the stratum corneum at locations of external pressure or friction. Also called callosity. Compare corn. 2. an unorganized network of woven bone formed about the ends of a broken bone; it is absorbed as repair is completed (provisional callus) and ultimately replaced by true bone (definitive callus). Also called keratoma. −callous, adj.
