Angular frequency is a measure of how quickly an object oscillates or rotates, defined as the rate of change of the phase of a sinusoidal waveform, usually expressed in radians per second. It connects to various physical systems, including harmonic oscillators and wave phenomena, providing insight into how systems evolve over time. In quantum mechanics, angular frequency plays a role in the time-dependent Schrรถdinger equation, where it relates to the energy of a system and the evolution of wave functions.