Look up: damping-ratio

1. 
   Damping ratio
   The `damping ratio` is defined as the ratio of the damping constant to the critical damping constant : zeta = frac. The damping ratio is unitless, because it is the result of dividing the units of the damping constant (N-s/m) by the critical damping constant (N-s/m), which cancels each other out. The `damping ratio` is a parameter, usually denoted by ζ (zeta), that characterizes the frequency response of a second order ordinary differen...
   Found on http://en.wikipedia.org/wiki/Damping_rat
   
   
2. 
   Damping ratio
   ratio of actual damping to critical damping; if the damping ratio is less than one a system is said to be underdamped and if it is greater than one a system is said to be overdamped.
   Found on http://www.empiremagnetics.com/glossary/
   
   
3. 
   damping ratio
   for a linear time-invariant system of the second order described by the differential equation the damping ratio is the value of the factor ? NOTE 1 - ?_o is the characteristic angular frequency of the system. NOTE 2 - is the eigen angular frequency of the system.
   Found on http://www.electropedia.org/iev/iev.nsf/
   
   
4. 
   damping ratio
   ratio of the actual damping to the critical damping
   Found on http://www.electropedia.org/iev/iev.nsf/