There are two basic types of steam turbines. Those that discharge or exhaust into a condenser, normally under a deep vacuum, and those that don't. Those that don't discharge to a back pressure. The term non-condensing indicates one that discharges to a back pressure. (Even if that back pressure is atmospheric pressure.)
Non condensing turbines are typically used where there is the need for medium to low pressure steam for process, so steam is generated at higher pressures and let down through a non-condensing turbine which could be driving a generator or a mechanical drive (like a paper machine or a sugar cane grinding mill.)
While we are at it, then it should be mentioned that there is a type of turbine that is a combination of both, where some of the steam is condensed at the very bottom of the cycle, while the rest of the steam is taken from the turbine at some stage(s) above the condensing pressure for process uses. Extraction machines come in single, double, or triple extraction points. If anyone has seen more than 3, pipe up.
When talking about cogeneration there are two types:
"Bottoming" and "Topping".
Bottoming is where process steam is taken off the back side of the turbine instead of being condensed. Topping is where waste product or waste heat is used to make steam for turbine or other steam need.
Interesting trivia, but explains cogen philosopy quite well
