1846, "medical treatment of disease," from Modern Latin therapia, from Greek therapeia "curing, healing, service done to the sick; a waiting on, service," from therapeuein "to cure, treat medically," literally "attend, do service, take care of" (see therapeutic).
"art of curing mental diseases," 1892, from psycho- + therapy, on model of French psychothérapie (1889). In early use also of treatment of diseases by "psychic" methods (mainly hypnotism). Psychotherapeia was used in medical writing in 1853 as "remedial influence of the mind." Related: Psychotherapeutic (1890, in reference to hypnotic treatment); psychotherapeutics (1872).
"treatment of disease by the external application of metals," by 1856, from metallon, Greek source of metal (n.) + therapy.
First formulated as a system by Burq in 1848, and hence often called Burqism, it has been recently revived by Charcot. Simple disks of various metals are employed in contact with the external parts of the body, from which different therapeutic results are claimed. Other observers assert that all the phenomena described as following the application of metals may be produced by disks of wood, and that whatever curative results are attained are due to mental effects, rather than to any special virtues emanating from the metals themselves. [Century Dictionary, 1895]