(P) Program mode - exposure mode that allows the camera determines the optimum shutter speed/aperture combination for you.
Cameras can do this intelligently, for instance going for a faster shutter speed if you use a longer lens (to prevent blur due to shake). However, it is not clever enough to make any creative decisions for the photographer!
Additionally, cameras may have selectable modes for different subjects e.g. sport, night time, portrait. Whilst quite useful they are no substitute for the knowledge of why and when to vary exposure values!