In pipemaking, a drone is not an umanned aeriavel vehicle (UAV). The drone stands for a continuous sound, unchanged in pitch, that is sounded while the melody is being played. This can create several different harmonies or dissonances, depending on the melody. With bagpipes, the pipes that create this kind of sound are also called drone.
Usually the drones of bagpipes are tuned to the tonic, often in different octaves, e.g. in Uilleann Pipes. For some instruments, e.g. Schäferpfeifen, the drones could also be tuned in fourths or fifths, depending on musical context.