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prime verticalThe vertical circle that passes through an observer's zenith at right angles to the meridian and intersects the horizon at the east and west points (see cardinal points).
Prime Vertical(religion, spiritualism, and occult)
The prime vertical is the great circle that intersects the east point, the west point, the nadir, and the zenith at any given point on Earth. It is perpendicular to both the meridian and the horizon. Some systems of house division utilize this great circle as their primary point of reference, deriving the house cusps by dividing the prime vertical into 12 equal subdivisons.
the great circle of the celestial sphere that passes through the zenith and the eastern and western points on the horizon. The plane of the prime vertical is perpendicular to the plane of the horizon and the plane of the celestial meridian. All heavenly bodies, which pass through the prime vertical as a result of the diurnal motion, intersect the prime vertical at the same velocity with respect to altitude and azimuth (for a given terrestrial latitude).