Definition
An airplane whose wing has the shape of a triangle, with a sharply swept leading edge and a straight trailing edge that runs roughly perpendicular to the fuselage. The wing forms the Greek letter delta (Δ) when viewed from above. Delta wings are typically used on aircraft designed for high-speed or supersonic flight.
Plain English
An airplane with triangle-shaped wings, like the shape you see on the Concorde or many fighter jets.
Context Anchor
Seen in aircraft design, aircraft recognition, and airframe descriptions that identify an airplane by its wing shape.
Derivation
Named after the Greek capital letter delta (Δ), which is a triangle. The wing's outline matches that shape when viewed from directly above.
Why Pilots Care
Wing shape determines how an aircraft behaves at different speeds. Delta wings perform well at high speeds but generate lift differently at low speeds, often requiring higher angles of attack on approach and landing.
Intuition Check
Delta does not mean the airline here, and it does not mean a change in quantity. In this term, delta means triangle-shaped, from the shape of the Greek letter delta.
Example Sentence 1
The Concorde was a delta airplane, using its triangular wings to fly efficiently at supersonic speeds.
Example Sentence 2
Early supersonic fighters were often built as delta airplanes to reduce drag at high speeds.