Vibration /(?)/

Vi·bra·tion

Vibration

n.
  1. The act of vibrating, or the state of being vibrated, or in vibratory motion; quick motion to and fro; oscillation, as of a pendulum or musical string.
    As a harper lays his open palm Upon his harp, to deaden its vibrations.
  2. A limited reciprocating motion of a particle of an elastic body or medium in alternately opposite directions from its position of equilibrium, when that equilibrium has been disturbed, as when a stretched cord or other body produces musical notes, or particles of air transmit sounds to the ear. The path of the particle may be in a straight line, in a circular arc, or in any curve whatever. (Physics)

Phrases & Compounds
Amplitude of vibration
the maximum displacement of a vibrating particle or body from its position of rest.
Phase of vibration
any part of the path described by a particle or body in making a complete vibration, in distinction from other parts, as while moving from one extreme to the other, or on one side of the line of rest, in distinction from the opposite. Two particles are said to be in the same phase when they are moving in the same direction and with the same velocity, or in corresponding parts of their paths.