What is the meaning of Waterspout?

A whirlwind that forms over water, not associated with a mesocyclone of a thunderstorm (contrary to a true tornado).

A true tornado that passes over a body of water.

A plume of water rising from the surface of a body of water as the result of an impact or explosion.

A channel through which water is discharged, especially from the gutters of a roof.

Source: wiktionary.org