Question

define frequency of vibration and oscillation

Answer 1

t and fro position between any two points is called ocillatry motion

Answer 2

When the energy of a vibrating system is gradually dissipated by friction and other resistances, the vibrations are said to be damped. The vibrations gradually reduce or change in frequency or intensity or cease and the system rests in its equilibrium position.
For cyclical processes, such as rotation, oscillations, or waves,frequency is defined as a number of cycles per unit time.