The condition (of the skin or other tissue) of being abnormally hardened or thickened; the condition of being callused. Cf. callousness, n. 1a.

The condition (of tissue) of being abnormally hardened or thickened, spec. callused condition of the skin, typically resulting from repeated…

the fact or condition of being imperspirable.

(a) (see quot. 1844); now rare or Obsolete; (b) excessive development of the horny layer of the skin.

A chronic hardened condition of the skin, resulting from hypertrophy of connective tissue.

= scleroderma, n.

Originally: abnormal keratinization or cornification; any disorder characterized by this. Later: spec. retention of nuclei by cells of the stratum…

Disease of the skin affecting the prickle-cell layer (stratum spinosum) of the epidermis; hyperplasia of prickle cells; an instance of this.

Pathology. An inflammatory disease of the eyelids, characterized by thickening and hardening of their edges.

Hardening and thickening of the skin caused by scratching or other continued irritation; an area of skin so affected.

(see quot. 1976).