I have an Indian passport, and I will be traveling from India to Switzerland on a multiple entry visa. I have applied for a Turkish visa and will travel to Turkey also. Can I reenter Switzerland after my Turkish visit?
Yes. That's what "Multi-entry" means - you may enter multiple times before the expiry of the visa.
Note that presuming your visa only allows 90 days per stay within a 180 day period, this 90 days will NOT reset when you leave and re-entry from Turkey.