The definition of a gym, short for gymnasium, is a room or building where people go to play sports or exercise.
An example of a gym is where the contestants on The Biggest Loser go to lift weights.
- A gymnasium.
- A course in physical education.
- A metal frame supporting equipment used in outdoor play.
(third-person singular simple present gyms, present participle gyming, simple past and past participle gymed)
- (intransitive) To go the gym.
- On Wednesdays I hike; on Fridays I gym.