1. The detection of radiation by the body which is a process believed by some to be responsible for the operation of dowsing rods, pendulums, etc. as a means of locating buried substances, diagnosing illness, etc.: Allan was amazed by the results of the radiesthesia he witnessed when his uncle used the dowsing rods to detect water on his property.
2. Detecting and diagnosing a disease by the passing of a person's hands over a body: In addition to normal medical procedures, Dr. Small was also known to use radiesthesia to detect illnesses in his patients.