noun

1. 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.

2. The lowest point; time of greatest depression.

3. The axis of a projected conical shadow; the direction of the force of gravity at a location; down.

   “The nadir of the sun is the axis of the shadow projected by the Earth.”

Synonyms: bathos, lowest ebb, slough of despond, trough, down

verb

1. To extend (a beehive) by adding an empty box at the base.