well wikipedia comes to the rescue once again! here is their definiton of damping:
The term damping factor can also refer to the ratio between a source and load impedance.
Damping is any effect, either deliberately engendered or inherent to a system, that tends to reduce the amplitude of oscillations. The term "dampening" is sometimes incorrectly used instead of "damping"; "dampening" simply means to get something wet by applying water.
In applied mathematics, damping is mathematically modelled as a force with magnitude proportional to that of the velocity of the object but opposite in direction to it. Thus, for a simple mechanical damper, the force F is related to the velocity v by
\bold{F} = -B \bold{v}
where B is the damper constant.
This relationship is perfectly analogous to electrical resistance. See Ohm's law.
In playing stringed instruments such as guitar or violin, damping is the quieting or abrupt silencing of the strings after they have been sounded, by pressing with the edge of the palm, or other parts of the hand such as the fingers on one or more strings near the bridge of the instrument. The strings themselves can be modelled as a continuum of infinitesimally small mass-spring-damper systems where the damping constant is much smaller than the resonant frequency, creating damped oscillations (see below). See also Vibrating string.
http://en.wikipedia.org/wiki/Damping