Xerosis is the medical term for abnormal dryness of the skin, eyes, or other tissues — from the Greek xeros, dry. Xerosis of the skin is the familiar winter complaint: rough, flaking, itchy skin when cold air and indoor heating strip moisture, worsened by harsh soaps and ageing. It is managed with moisturisers, gentle cleansing, and humidified air. In nutrition, xerosis of the eye is an early stage of vitamin A deficiency. The word simply names dryness as a clinical finding, across contexts from dermatology to ophthalmology. While usually a minor nuisance, persistent xerosis deserves attention — skin is a barrier, and a breached barrier invites infection.