(aircraft) An aircraft that is borne along by one or more sets of long rotating blades which allow it to hover, move in any direction including reverse, or land; and typically having a smaller set of blades on its tail to stabilize the aircraft.
A powered troweling machine with spinning blades used to spread concrete.
(botany) The winged fruit of certain trees, such as ash, elm, and maple.
(zoology, slang) A dragonfly; so named due to its resemblance to a helicopter (sense 1).