Rotorhead
In helicopters the rotorhead is the part of the rotor assembly that joins the blades to the shaft, cyclic and collective mechanisms. It is sometimes referred to as the rotor "hub". The rotorhead is where the lift force from the rotor blades act. The rotorhead is connected to the main drive shaft via the Jesus nut, and houses several other components such as the swash plate, flight control linkages and fly-bars. The rotor hub is also where the centre of gravity acts on the helicopter.