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.
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.

3. Vibration and oscillation are both used, in mechanics, of the swinging, or rising and falling, motion of a suspended or balanced body; the latter term more appropriately, as signifying such motion produced by gravity, and of any degree of slowness, while the former applies especially to the quick, short motion to and fro which results from elasticity, or the action of molecular forces among the particles of a body when disturbed from their position of rest, as in a spring.

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.

4. A supernatural emanation, bearing good or ill, that is sensed by or revealed to those attuned to the occult.
5. Often, vibrations; informal: A general emotional feeling one has from another person or a place, situation, etc.: "I usually get good vibrations when I am around her."