What is the full meaning of Mercedes?

It was the name of Emil Jellinek's daughter. He bought a number of vehicles from the company that later on became "Mercedes."

He (Emil) bought a car from the "Daimler Motoren Gesellschaft" (DMG) company on the 22nd December 1900, and had installed a specially designed engine that had been named " Mercédès" after his daughter.

THe success of this car, and others, in racing later on led the DMG to adopt the name "Mercedes" in place of DMG.

Beyond this it has no more meaning than any other name.