ther·a·py (th?r??-p?)n. pl. ther·a·pies 1. Treatment of illness, injury, or disability.2. Psychotherapy.3. Healing power or quality: the therapy of fresh air and sun.[New Latin therapia, from Greek therapeia, from therapeuein, to treat medically; see therapeutic.]American Heritage® Dictionary of the English Language, Fifth Edition. Copyright © 2016 by Houghton Mifflin Harcourt Publishing Company. Published by Houghton Mifflin Harcourt Publishing Company. All rights reserved.therapy (???r?p?) n, pl -pies (Medicine) a. the treatment of physical, mental, or social disorders or diseaseb. (in combination): physiotherapy; electrotherapy. [C19: from New Latin therapia, from Greek therapeia attendance; see therapeutic]Collins English Dictionary ? Complete and Unabridged, 12th Edition 2014 © HarperCollins Publishers 1991, 1994, 1998, 2000, 2003, 2006, 2007, 2009, 2011, 2014ther?a?py (???r ? pi) n., pl. -pies. 1. the treatment of disease or disorders, as by some remedial, rehabilitative, or curative process: speech therapy. 2. psychotherapy. 3. a curative power or quality. 4. any act, task, program, etc., that relieves tension. [1840?50;