is an equestrian event consisting of speed pattern racing and timed games for riders on horses. These events often emphasize children’s participation and may be organized by a recognized Pony Club or a 4-H club. In parts of the western United States, this type of competition is usually called an “O-Mok-See” (also spelled “omoksee” or without hyphenation as “o mok see”) competition, a term derived from a Native American phrase said to mean “games on horseback.” Very small events with little or no prize money, designed for beginners or riders at a local level, are sometimes called playdays. Gymkhana is the word used in most of the rest of the English-speaking world, including the United Kingdom, and both the east and west coasts of the United States.

https://en.wikipedia.org/wiki/Glossary_of_equestrian_terms