Mathematically, the Pole of the Horizon. The point directly overhead, through which pass the Prime Vertical (q.v.) and Meridian circles. Every place has its own zenith, and the nearer a planet is to that zenith, the more powerful is its influence.. The term is sometimes loosely applied to the cusp of the Tenth House, which strictly speaking is only the point of the zodiac or ecliptic through which the meridian circle passes. v. Celestial Sphere.
ASTROLABE ENCYCLOPEDIA
