natural or man-made gap in vegetation that acts as a barrier against wildfires
Plow cutting a firebreak in advance of a forest fire, South Carolina
Rocky Point Trail acted as a firebreak for a forest fire in McDonald Lake region of Glacier National Park, Montana, USA in summer 2003
A Firebreak is a way to fight fires. In a firebreak, there is no vegetation, or other material that can burn. This makes it hard for a fire to jump across the break. Therefore, the spread of a possible fire is delayed.