'main rotor' definitions:

Definition of 'main rotor'

From: WordNet
noun
Rotor consisting of large rotating airfoils on a single- rotor helicopter that produce the lift to support the helicopter in the air

Definition of 'main rotor'

From: GCIDE
  • main rotor \main rotor\ n. (Aviation) The assembly of large rotating airfoils (blades) on a helicopter that produce the lift to support the helicopter in the air. [WordNet 1.5]