Balneotherapy can be defined as all therapies in which thermal mineral water baths or pools are the main focus. It typically involves bathing in natural thermal lakes or ponds, but can also involve bathing in swimming pools filled with thermal water or with a direct tap to the thermal source. The word balneotherapy is of Greek origin and is composed of "balneo", meaning "bath", and "therapy", meaning "treatment" or "health treatment". referedbath therapy".
Baths are of course inseparable from water, so balneotherapy is also a subgroup of hydrotherapy (healing through water). Within balneotherapy there are in turn special sub-forms such as the thermal therapies, the thalasso therapy or the Kneipp therapy, in each of which only special water is used.
Should you ever stumble across the term "balneology": this refers to the study of healing through baths.