1. The therapeutic passing of high-frequency electric currents through the body by means of external electrodes in order to generate heat within the body.
2. Medical diathermy, in which the tissues are warmed but not sufficiently to change their nature.
3. Surgical diathermy, in which there is sufficient heating to produce a local change such as destruction of tissue or coagulation of bleeding vessels.
4. Local elevation of temperature within the tissues, produced by high frequency current, ultrasonic waves, or microwave radiation.

A procedure that uses an electrical current to stop bleeding and to cause destruction of tissue: Electrocoagulation is a therapeutic destructive form of electrosurgery in which tissue is hardened by the passage of a high-frequency current from an electric cautery device.

Surgical diathermy is a method of sealing blood vessels using heat generated by a high-frequency electric current through fine needles or an electrical surgical knife.

The procedure is used during surgery to close newly cut vessels and it can also be used to stop nosebleeds and to remove vascular deformities.