gelo-, geloto- +

The use of humor as a form of therapy in the treatment of illness by getting the patient to laugh.

1. Loss of muscle tone induced by laughter.
2. A sudden loss of muscle tone (cataplexy) caused by uproarious (loud and unrestrained) laughter.

1. A laughter researcher.
2. Someone who specializes in gelotology, the study of humor, laughter, and the exercising of the gelastic muscles, a deeply serious exploration of what happens to the physical systems; such as, respiration and circulation, when people are exposed to humor.

Gelotologists are serious people who study laughter, and they would be the first to tell you that the results of their research is very much a laughing matter.

1. A psychological and physiological study of laughter.
2. The study of humor and laughter, and its effects on the body.

A gauge for measuring laughter

1. To express mirth, pleasure, derision, or nervousness with an audible, vocal expulsion of air from the lungs that can range from a loud burst of sound to a series of quiet chuckles and is usually accompanied by characteristic facial and bodily movements.
2. The act or sound of laughing; laughter.
3. Informally, something that provokes laughter, amusement, or ridicule: "After all the advance publicity, the political speech turned out to be a laugh."
4. To have the last laugh, to prove ultimately successful after an apparent defeat or loss: "She smiled slyly when she completed the race, because she knew she would still have the last laugh on her critics."

1. Happiness, gladness, gaiety, or enjoyment, especially when accompanied, or expressed, by laughter.
2. Great merriment, amusement, or laughter.

Although not directly derived from this gelo- unit, "mirth" has a significant relationship with this family.

A hatred of laughter.