Plain English Meaning
A training exercise where you deliberately stall the airplane with the engine at high power, the way it might stall by accident just after takeoff or during a climb, then practice recovering smoothly.
Full Definition
A practice maneuver in which the pilot intentionally induces an aerodynamic stall while the engine is producing takeoff or climb power, simulating the conditions that cause an inadvertent stall during takeoff, departure, or climb-out. The airplane is slowed to liftoff or climb speed, full or near-full power is applied, and the nose is raised until the stall occurs, after which the pilot recovers with a reduction, full power, and minimal loss.