Frequency

Frequency is the number of occurrences of a repeating event per unit of time. Frequency is an important parameter used in science and engineering to specify the rate of oscillatory and vibratory phenomena, such as mechanical vibrations, audio signals (sound), radio waves, and light.

rate of change of the phase angle

frequency at which a specific weapon can fire or launch its projectiles

thumb|upright=0.65|The hourglass is often used as a symbol representing the passage of time. thumb|Clocks; a watch-maker seated at his workbench Chronometry or horology () is the science studying the measurement of time and timekeeping. Chronometry enables the establishment of standard measurements of time, which have applications in a broad range of social and scientific areas. Horology usually refers specifically to the study of mechanical timekeeping devices, while chronometry is broader in scope, also including biological behaviours with respect to time (biochronometry), as well as the dat

frequency-domain analysis method