The sideslip angle, also called angle of sideslip (AOS, AoS, β {\displaystyle \beta } , Greek letter beta), is a term used in fluid dynamics and aerodynamics and aviation. It relates to the rotation of the aircraft centerline from the relative wind. In flight dynamics it is given the shorthand notation β {\displaystyle \beta } (beta) and is usually assigned to be "positive" when the relative wind is coming from the right of the nose of the airplane.