Plain English Meaning
When an airplane flies, the air pressure under the wing is higher than the air pressure above it. At the wingtip, the higher-pressure air rolls up and around to the lower-pressure side, forming spinning tubes of air that trail behind the plane. These spinning tubes are called wingtip vortices.
Full Definition
The natural production of swirling air currents (vortices) at the wingtips of an aircraft in flight, caused by the pressure difference between the higher-pressure air below the wing and the lower-pressure air above it. As the aircraft moves through the air, this pressure difference causes air to spill around the wingtip from below to above, creating a rotating cone of air that trails behind each wingtip.
Context Anchor
Seen in wake turbulence discussions, especially when spacing behind another aircraft for , , or .