soliton

A soliton is a stable, isolated wave that travels at a constant speed. As a soliton travels, its shape does not change and it does not dissipate. If it collides with another wave, it emerges from the collision unscathed. In a sense, it is a wave that behaves like a particle. Solitons have been predicted and observed in nearly every medium in which waves propagate, including fluids such as water, transparent solids such as optical fibers, and magnets.