A drone is an unmanned aerial vehicle, also known as a UAV. It is an aircraft with no human pilot on board, instead its flight is controlled by computers in the vehicle or a remote control by a pilot on the ground.
Originally they were deployed for military and special operation units, and then also used
in a number of civil applications, such as policing
and firefighting, and nonmilitary security work, such as surveillance of
Drones are a wide variety of shapes and sizes and characteristics. Historically, UAVs were simple remotely piloted aircraft, but autonomous control is increasingly being employed. Amazon intends to launch Prime Air, its unmanned flying delivery service in 2015, here's this video: