- any of a number of contagious skin diseases caused by certain parasitic fungi and characterized by the formation of ring-shaped eruptive patches.
- any of various fungal infections of the skin (esp the scalp) or nails, often appearing as itching circular patchesAlso called: tinea
- Any of a number of contagious fungal infections of the skin, hair, or nails caused chiefly by species of the genera Microsporum, Trichophyton, and Epidermophyton. Ringworm often causes scaly, itching ring-shaped patches, especially on the skin. Also called tinea