Plain English Meaning

The fastest the airplane can go while staying level, with the engine pushed to its full output for that altitude. Go any faster and it would have to descend; go slower and there is power left over to climb.

Full Definition

The highest airspeed an airplane can sustain in straight-and-level flight at a given altitude and weight, with the engine producing maximum available thrust or power. At this speed, all available thrust is being used to overcome drag, leaving no surplus power to accelerate or climb.

Context Anchor

Seen in airplane control and energy-management discussions, especially when explaining how elevator and power affect altitude, speed, and the airplane’s .