Definition
The minimum airspeed at which an airplane can maintain level flight in a given configuration and load condition. Below this speed, the wing's angle of attack required to support the aircraft exceeds the critical angle, the airflow separates from the upper wing surface, and lift drops sharply. Stall speed varies with weight, load factor (bank angle and G-loading), configuration (flaps, gear), and power setting.
Plain English
The slowest speed at which the wings can still produce enough lift to keep the airplane flying. Go slower than that, and the wing stops flying.
Context Anchor
You will see stall speed discussed during slow flight, takeoffs, landings, turns close to the ground, and ground-reference maneuvers where airspeed and bank angle must be managed carefully.
Derivation
Stall' comes from an old word meaning to stop or come to a standstill. In aviation it doesn't mean the engine stops -- it means the wing stops producing lift effectively.
Why Pilots Care
Stall speed rises with bank angle and load factor, so pilots must keep a safe margin above it to avoid an unintentional stall during maneuvering near the ground.
Grounding Statement
In a steeper turn, an airplane can stall at a higher airspeed than it would in straight-and-level flight.
Intuition Check
Do not assume stall speed is a single fixed number for all flying. It changes with the airplane’s weight, setup, and how sharply it is turning.
Example Sentence 1
As the pilot rolled into a steep 60-degree bank, the stall speed nearly doubled, so they added power to maintain altitude.
Example Sentence 2
The student adjusted pitch and power to maintain a margin above stall speed during the downwind leg of the ground reference pattern.