What does dsa on your volva dash mean?

If you mean a Volvo ....

Dynamic Stability Assistance

Your car can be fitted with Dynamic Stability Assistance (DSA). This is a system that helps prevent wheel spin. It comes on automatically each time you start the car. It operates automatically at all speeds if one or both driven wheels start spinning. The ABS sensors tell the engine management system that the wheels are turning at different speeds. The engine management system then reduces power to the engine via the fuel injectors in 16 steps until no further wheel spin occurs.