Plain English Meaning
The hardest steady slowdown the airplane can keep up during the landing rollout — not a quick jab on the brakes, but a strong, even slowing held all the way through.
Full Definition
The maximum sustained rate at which an aircraft's speed decreases during the landing roll, achieved when braking, aerodynamic drag, and other retarding forces are applied at their highest effective level continuously rather than in brief bursts.
Context Anchor
Seen in landing performance discussions when explaining how braking affects the distance needed to stop after touchdown.
Derivation
Continuous means kept up without pause. Peak means the highest level reached. Deceleration comes from Latin de- (down from) and celer (swift) — literally 'slowing down.' Together: the strongest slowing, held steadily.
Why Pilots Care
It directly determines the runway length required to stop safely under given .