The Vietnamese word "cầu phao" refers to a "pontoon bridge." A pontoon bridge is a type of bridge that is supported by floating structures (pontoons) rather than being built on solid ground. This kind of bridge is often used in places where traditional bridges cannot be built due to water or unstable ground.
While "cầu phao" primarily means "pontoon bridge," in some contexts, it could refer to any floating structure that serves as a bridge or passageway over water.