1) Infection with a fungus of the genus Candida. It is usually a superficial infection of the moist areas of the body and is generally caused by Candida albicans.

2) A condition in which Candida albicans, a type of yeast, grows out of control in moist skin areas of the body. It is usually a result of a weakened immune system, but can be a side effect of chemotherapy or treatment with antibiotics. Thrush usually affects the mouth (oral thrush); however, rarely, it spreads throughout the entire body.