What does Boxing Day have to do with boxing?
1846, "medical treatment of disease," from Modern Latin therapia, from Greek therapeia "curing, healing," from therapeuein "to cure, treat medically," literally "attend, do service, take care of;" related to therapon "servant, attendant."
therapy ther·a·py (thěr'ə-pē)
The treatment of illness or disability.
A healing power or quality.
Treatment intended to cure or alleviate an illness or injury, whether physical or mental.