Occupational Therapy (OT) is the "use of productive or creative activity in the treatment or rehabilitation of physically or emotionally disabled people" (American Heritage Dictionary).
A more technical definition is that OT is the use of meaningful occupation to assist people who have difficulty in achieving a healthy and balanced lifestyle and to enable an inclusive society so that all people can participate to their potential in daily occupations of life.
Occupational therapists work with a variety of individuals who have difficulty accessing or performing meaningful occupations.
Most commonly, occupational therapists and occupational therapy assistants work with people with disabilities to enable them to maximize their skills and abilities.
Occupational therapy gives people the "skills for the job of living" necessary for "living life to its fullest."
See Wikipedia, Occupational therapy.