Angular velocity
In kinematics, angular velocity (symbol ω or ω → {\displaystyle {\vec {\omega }}} , the lowercase Greek letter omega), also known as the angular frequency vector, is a three-dimensional Euclidean vector that uniquely identifies the plane, direction and angular speed of rotation of a particle rotating in a circle at constant speed in three dimensions. The direction ω ^ = ω / ‖ ω ‖ {\displaystyle {\hat {\boldsymbol {\omega }}}={\boldsymbol {\omega }}/\|{\boldsymbol {\omega }}\|} is normal to the instantaneous plane of rotation.