Gym as "gym, gym" is an informal usage, and the formal usage should be written as gym.
gymnasium
Phonetic symbols are English [dm] and American [dm]
Deformation complex number: gyms
use
1, fitness center; Gym; Gymnasium (countable noun)
A gym is a club, a building or a big room, usually containing special equipment, where people go for physical exercise and fitness.
2. Fitness; Sports activities (uncountable nouns), esp in schools
Gymnasium is an activity of physical exercise in gymnasium, especially in school.
example sentence
1、The？ Gym? It can be used by both able-bodied and disabled people.
This gym can be used by both the able-bodied and the disabled.
While the boys are playing golf, I exercise on the playground. Gym.
While the boys are playing golf, I exercise in the gym.
3、The？ Gym? The teacher asked us to stand in a row against the concrete wall.
The PE teacher asked us to stand in a row against the wall.
Every Sunday we go to the nearest gymnasium to play badminton.
Every Sunday we go to the nearest gymnasium to play badminton.
The gym is his favorite sport.
Gymnastics is his favorite sport.