- 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: <i>synonym</i>: <strong> summit</strong>.
- The vertical point of the heavens at any place, or the point directly above an observer's head; the upper pole of the celestial horizon. The opposed pole is the nadir.
- Figuratively, the highest point, or summit, as of one's fortune; the culmination.
- That point in the visible celestial hemisphere which is vertical to the spectator; the point of the heavens directly overhead; -- opposed to <ant>nadir</ant>.
- hence, figuratively, the point of culmination; the greatest height; the height of success or prosperity.
- See under <er>Distance</er>.
- See <er>Sector</er>, 3.
- a telescope specially designed for determining the latitude by means of any two stars which pass the meridian about the same time, and at nearly equal distances from the zenith, but on opposite sides of it. It turns both on a vertical and a horizontal axis, is provided with a graduated vertical semicircle, and a level for setting it to a given zenith distance, and with a micrometer for measuring the difference of the zenith distances of the two stars.
- The point in the sky <xref>vertically</xref> above a given position or observer; the <xref>point</xref> in the <xref>celestial sphere</xref> opposite the <xref>nadir</xref>.
- The <xref>highest</xref> point in the sky reached by a <xref>celestial body</xref>.
- Highest point or <xref>state</xref>; <xref>peak</xref>.
- the point above the observer that is directly opposite the nadir on the imaginary sphere against which celestial bodies appear to be projected