Colloquial short form for a fitness studio; a place where you can work out and use exercise equipment.
example
Nach der Arbeit gehe ich heute noch ins Gym, um Krafttraining zu machen.
After work, I'm going to the gym today to do strength training.
Usage tips
Register: colloquial language
'Gym' is a very informal and modern short form for 'Fitnessstudio' (gym/fitness studio). It is used mainly in spoken language and among younger people.
EXAMPLE
Kommst du später mit ins Gym?
Are you coming to the gym later?
Origin of the word
The word 'Gym' (gym) is an Anglicism and was taken directly from English. This also explains its informal and modern character in German.
EXAMPLE
Viele neue Wörter wie „Gym“ kommen aus dem Englischen.
Many new words like 'Gym' come from English.
Correct preposition
To express movement, you use 'ins Gym gehen' (to go to the gym; accusative). When describing the place where you are, you say 'im Gym sein' (to be at/in the gym) or 'im Gym trainieren' (to work out at/in the gym; dative).