Definition of "quadcopter"

In April, as an Air Canada Jazz flight was landing at Trudeau Airport, a drone came so close the pilot was able to identify it as a quadcopter.

2017 October 17, Christina Caron, “After Drone Hits Plane in Canada, New Fears About Air Safety”, in New York Times‎

he saw, sweeping back and forth over the treetops, a sleek-looking quadcopter drone.

2023, Eleanor Catton, Birnam Wood, page 235