Plain English Meaning
Getting the airplane safely on the ground when something has gone wrong — usually an engine failure — by gliding to the best landing spot you can reach and flying a planned approach to it.
Full Definition
A maneuver in which a pilot, faced with an actual or simulated loss of engine power or other in-flight emergency, selects a suitable landing area and flies a planned glide and approach to put the airplane safely on the ground without engine power available for a normal go-around.
Context Anchor
Seen in flight training when an instructor teaches or evaluates how a pilot handles a simulated engine failure or other urgent situation that requires without delay.