In fluid dynamics, a wake is the region of turbulence in front of, immediately to the rear of, and to the sides behind a solid body moving relative to the water, caused by the flow of liquid under, over or around the body. The wake leading the body is caused by the compression of the liquid medum by the moving body, and is often called a bow wake when observed preceeding a watercraft. As with all wave forms, it spreads outward from the source until it's energy is overcome or lost, usually by friction or dispersion.
Wakes are occasionally used recreationally, as people riding personal watercraft, and aquatic mammals such as dolphins, can ride the leading edge of a wake.
In science fiction the term wake is also used to refer to the residue effect caused by faster than light travel.