Plain English Meaning
How quickly the airplane is going up, measured in feet per minute.
Full Definition
The vertical speed at which an airplane is gaining altitude, expressed in feet per minute (fpm) and shown on the vertical speed indicator (VSI). Climb rate depends on excess power available beyond what is needed to maintain level flight, and it varies with airspeed, weight, configuration, and density altitude.
Context Anchor
You will see climb rate in climb performance discussions, training maneuvers, and cockpit checks that compare how quickly the airplane is gaining altitude.