solitary wave

(noun) (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. Synonyms: soliton, soliton wave, solitary wave. Example: "Soliton waves can travel long distances with little loss of energy or structure."