That point in the visible celestial hemisphere which is vertical to the spectator; the point of the heavens directly overhead; -- opposed to nadir.
- The point on the celestial sphere that is directly above the observer.
- The upper region of the sky.
- The highest point above the observer's horizon attained by a celestial body.
- The point of culmination; the peak: the zenith of her career. See Synonyms at summit.