Definition
A fabric cone or sleeve mounted on a freely rotating pole at an airport, used to indicate surface wind direction and provide a rough estimate of wind speed. The open end faces into the wind, so the sock points downwind. The angle the sock makes relative to its pole gives a visual estimate of wind strength: fully extended horizontally indicates a strong wind, while a limp or drooping sock indicates light or calm conditions.
Plain English
A fabric tube on a pole at the airport that shows pilots which way the wind is blowing and roughly how strong it is. The wind blows into the open end and pushes the sock out behind it.
Context Anchor
A pilot checks a windsock before takeoff or landing, especially when deciding how much wind is blowing across the runway.
Derivation
From 'wind' plus 'sock,' because the device looks like a long sock or stocking blowing in the breeze. The name describes exactly what it is.
Why Pilots Care
Provides immediate visual confirmation of wind direction and strength before every takeoff or landing, helping pilots choose the correct runway and apply proper crosswind technique.
Intuition Check
Do not assume the narrow end points to where the wind is coming from. The open end faces the wind; the narrow end points where the wind is going.
Example Sentence 1
Before lining up for takeoff, the pilot glanced at the windsock and confirmed a steady crosswind from the left.
Example Sentence 2
The windsock stood out straight and steady, showing a steady crosswind from the left.