(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 WordNet 3.0 & Open English WordNet

In mathematics and physics, a soliton is a nonlinear, self-reinforcing, localized wave packet that is strongly stable, in that it preserves its shape while propagating freely, at constant velocity, and recovers it even after collisions with other such localized wave packets. Wikipedia

Type of self-reinforcing solitary wave. Wikipedia Disambiguation

Self-reinforcing solitary wave packet that maintains its shape while it propagates at a constant velocity Wikidata

A self-reinforcing pulse or travelling wave caused by any non-linear effect (found in many physical systems). Wiktionary

Self-reinforcing travelling wave. Wiktionary (translation)