Pilot here with a Mooney. If you've never heard of Mooney go to
www.mooney.com
I'm certified as a Private Pilot with single engine privileges. I also have an instrument rating which is an operating privilege that is attached to the pilot certificate. It allows me to navigate and control the airplane without visual reference to the ground, such as when flying in clouds. This is done only with reference to the instruments on the airplane. It requires additional training and instruction beyond what is required for a Private Pilot certificate, including rules and procedures specific to instrument flying, additional instruction in meteorology and more intensive training in flight solely by reference to instruments.
Herb