Question

what is oscillation?​

Answer 1

$\blacksquare$ Oscillation

Oscillation is the repetitive variation, typically in time, of some measure about a central value or between two or more different states. The term vibration is precisely used to describe mechanical oscillation. Familiar examples of oscillation include a swinging pendulum and alternating current.

Answer 2

the to and fro motion of the pendulum is termed as oscillation

oscillations

are calculated to check the gravity at a place by using simple pendulum