Source : WordNet®

soliton
     n : (physics) a quantum of energy or quasiparticle that can be
         propagated as a traveling wave in nonlinear systems and
         is neither preceded nor followed by another such
         disturbance; does not obey the superposition principle
         and does not dissipate; "soliton waves can travel long
         distances with little loss of energy or structure" [syn:
         {soliton wave}, {solitary wave}]