n.
Upward-acting force on an aircraft wing or airfoil .
An aircraft in flight experiences an upward lift force, as well as the thrust of the engine, the force of its own weight, and a drag force. The lift force arises because the speed at which the displaced air moves over the top of the airfoil (and over the top of the attached boundary layer ) is greater than the speed at which it moves over the bottom and because the pressure acting on the airfoil from below is therefore greater than the pressure from above.