Oscillation is motion back and forth repeatedly around a central value or equilibrium point between two positions or states. Without an external force, oscillation of an object dissipates energy due to friction, which slows it down and ultimately ends the movement; however, it can be made into a continuous movement through the application of an appropriate external force.
Oscillation occurs in virtually every form or aspect of matter and energy, including physical, electronic, biological, cosmic and even economic systems. Examples include the pendulum of a clock, a child swinging on a swing, oscillator electronic circuits, the beating of the human heart, predator–prey population cycles, the periodic swelling and contraction of some stars and business cycles.
The term vibration is used to describe oscillation in mechanical systems. A vibration is always an oscillation, but an oscillation is not necessarily a vibration.