What do you mean Ringworm isn't caused by a Worm?

Ringworm is the common name for tinea corporis.  Tinea corporis is an an infection of the skin caused by any of a number of fungi.  It is sort of like athlete's foot, tinea pedis, of the body.  Usually this infection responds quickly to any of a number of topical antiyeast creams as long as the patient has a normal immune system.