The delta wing is a wing

Wing

A wing is an appendage with a surface that produces lift for flight or propulsion through the atmosphere, or through another gaseous or liquid fluid...

 planform

Planform

In aviation, a planform is the shape and layout of a fixed-wing aircraft's fuselage and wing. Of all the myriad planforms used, they can typically be grouped into those used for low-speed flight, found on general aviation aircraft, and those used for high-speed flight, found on many military...

 in the form of a triangle. It is named for its similarity in shape to the Greek uppercase letter delta

Delta (letter)

Delta is the fourth letter of the Greek alphabet. In the system of Greek numerals it has a value of 4. It was derived from the Phoenician letter Dalet...

 (Δ).
Between 1529 and 1556 Conrad Haas

Conrad Haas

Conrad Haas was a military engineer of the Holy Roman Empire, who is believed to be the first person to describe a multistage rocket in writing.Haas was perhaps born in Dornbach...

 wrote a book in which he described rocket

Rocket

A rocket is a missile, spacecraft, aircraft or other vehicle which obtains thrust from a rocket engine. In all rockets, the exhaust is formed entirely from propellants carried within the rocket before use. Rocket engines work by action and reaction...

 technology, involving the combination of fireworks and weapons technologies. This manuscript was re-discovered in 1961, in the Sibiu public records (Sibiu public records Varia II 374).