nadir

(noun): The point of the celestial sphere, directly opposite the zenith; inferior pole of the horizon; point of the celestial sphere directly under the place of observation.
(noun): The lowest point; time of greatest depression.
(noun): The axis of a projected conical shadow; the direction of the force of gravity at a location; down.
(noun): An empty box added beneath a full one in a beehive to give the colony more room to expand or store honey.
(verb): To extend (a beehive) by adding an empty box at the base.