Plain English Meaning

Descent is the part of a flight where the airplane is purposely going down to a lower altitude.

Full Definition

A controlled phase of flight in which the airplane loses altitude in a planned, deliberate manner, achieved by reducing power, lowering the pitch attitude, or both, while maintaining airspeed within prescribed limits.

Context Anchor

Seen on phase-of-flight checklists, especially when preparing to leave level flight and move toward landing.

Derivation

From the Latin descendere, meaning 'to climb down' (de- 'down' + scandere 'to climb'). The aviation meaning keeps that original sense — moving downward in a controlled way.