Find the word definition

Wiktionary
gelotology

n. The study of humor and laughter, and its effects on the body.

Wikipedia
Gelotology

Gelotology (from the Greek gelos, meaning laughter) is the study of laughter and its effects on the body, from a psychological and physiological perspective. Its proponents often advocate induction of laughter on therapeutic grounds in alternative medicine. The field of study was pioneered by William F. Fry of Stanford University.