- noun a place where water rises naturally to the surface
- noun a pool of water created by boring holes in the ground
- Term applied by exobiologists to the 18–21cm wavelength region in radio astronomy. This waveband encompasses the principal radio emissions due to hydrogen and the hydroxyl ion, the components of water. Because of the overwhelming importance of hydrogen as a component of the universe, the Waterhole could be a logical waveband for transmissions designed for interstellar reception, especially if, as on the Earth, water is of widespread importance as a constituent of living beings.