(1) An object formed by the solidification of a liquid poured into a mold. (2) Rigid encasement of a part, as with plaster, plastic, or fiberglass, for purposes of immobilization. (3) An elongated or cylindric mold formed in a tubular structure (e.g., renal tubule, bronchiole) that may be observed in histologic sections or in material such as urine or sputum; results from inspissation of fluid material secreted or excreted in the tubular structures. (4) Restraint of a large animal, usually a horse, with ropes and harnesses in a recumbent position. (5) In dentistry, a positive reproduction of the form of the tissues of the upper or lower jaw, which is made by the solidification of plaster, metal, or other materials, poured into an impression and over which denture bases or other dental restorations may be fabricated. [M.E. kasten, fr. O.Norse kasta] Cast: Treatments