Vibration refers to the to and fro motion of a particle or a body. It is used to describe the mechanical oscillation that occurs about the point of equilibrium. This oscillatory motion of the object can be periodic or random.
There are three different types of vibrations: free, forced, and damped vibrations.
When none of the characters are true, but the setting may be true, and what happens in the story actually happened in real life (at least some- most of it)