High Quality Content by WIKIPEDIA articles! Angle of attack (AOA, , Greek letter alpha) is a term used in fluid dynamics to describe the angle between a reference line on a lifting body (often the chord line of an airfoil) and the vector representing the relative motion between the lifting body and the fluid through which it is moving. Angle of attack is the angle between the lifting body`s reference line and the oncoming flow. This article focuses on the most common application, the angle of attack of a wing or airfoil moving through air.