The didtributor is a verry precise spinner. It spins distributing the sparks to each of the spark plug at he right time. The rotor, wich is acherly connected directly to sharft of the didtributor, is the mechanism that distributes the sparks.
Because it is connected to the distributor, the rotor also spins and makes contact with a number of points that corrosponed to the number of cylinders your engine has.
Modern distributors use electronic assistance that is able to alter the ignition's timing