It could potentially be a combination of:
* Ob - short for "obstetrics" (the branch of medicine dealing with pregnancy and childbirth)
* Gym - short for "gymnasium" (a place for physical exercise)
However, this combination doesn't make much sense in a typical context.
If you saw this term somewhere, please provide more context so I can help you figure out what it means. For example:
* Where did you see it?
* What was the surrounding text?
* What was the topic being discussed?
With more information, I can give you a more accurate answer.