late 14c., curacioun, "curing of disease, restoration to health," from Old French curacion "treatment of illness," from Latin curationem (nominative curatio), "a taking care, attention, management," especially "medical attention," noun of action from past-participle stem of curare "to cure" (see cure (v.)). From 1769 as "management, guardianship."
1650s, "curing, relieving, affording a remedy," from Late Latin remedialis "healing, curing," from Latin remedium "a cure, remedy, medicine, antidote, that which restores health," from re-, here perhaps an intensive prefix (or perhaps literally, "again;" see re-), + mederi "to heal" (from PIE root *med- "take appropriate measures").
Educational sense of "concerned with improving skills of students not as proficient as their peers or as required" is by 1879. In reference to physical exercise or training to overcome muscular or postural deficiencies, by 1925. Related: Remedially.
early 15c., "pertaining to curing; having the power to heal," from Old French curatif (15c.) "curative, healing" and directly from Latin curat-, past-participle stem of curare "to cure" (see cure (v.)). As a noun, "something that has power to heal, a remedy," by 1857.
"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).