Definition
The disturbed region of air left behind a moving aircraft, consisting of turbulent airflow and a pair of counter-rotating vortices trailing from the wingtips. The wake is produced as a by-product of generating lift and persists behind and below the aircraft for some distance before dissipating.
Plain English
The trail of churned-up, swirling air an aircraft leaves behind it as it flies.
Context Anchor
Seen in powerplant and airflow discussions, especially around propellers, fans, engine inlets, and parts that disturb smooth air.
Derivation
From Old Norse 'vök', meaning a hole or opening in ice — originally the track a ship cut through water. Aviation borrowed the term directly: just as a boat leaves a disturbed trail in water, an aircraft leaves a disturbed trail in air.
Why Pilots Care
Wake turbulence can roll or pitch a following aircraft dangerously, especially smaller planes behind heavier ones.
Analogy
A boat leaves a visible wake in water. An aircraft part can leave an invisible wake in air.
Intuition Check
Wake does not mean being awake here. It means the disturbed trail of air left behind an object.
Example Sentence 1
The tower instructed the small trainer to delay takeoff to allow the heavy jet's wake to dissipate.
Example Sentence 2
Controllers space arrivals to avoid wake turbulence from the preceding heavy jet.