Glossary
What is rotor RPM?
How fast the rotor is turning. Managing it is central to flying a gyroplane, and the acceptable range is specific to the type. The figures that matter are in the aircraft flight manual for your aircraft, not in a general reference.
Also called Rrpm
That is the whole entry for now. The longer version, with the mechanics and worked examples, is still to be written. See autorotation for how those read once they exist.