Pronunciation: (bûrn'out"),[key] —n. 1. a fire that is totally destructive of something.
2. Also,burn'-out".fatigue, frustration, or apathy resulting from prolonged stress, overwork, or intense activity.
3. Rocketry. a. the termination of effective combustion in a rocket engine, due to exhaustion of propellant.
b. the end of the powered portion of a rocket's flight.
4. Elect.the breakdown of a lamp, motor, or other electrical device due to the heat created by the current flowing through it.