what is zenith

Zenith is an imaginary point directly "above" a particular location, on the celestial sphere. It is the "highest" point on the celestial sphere and is vertically opposite to the nadir, which is the point directly below the observer. The term zenith can also refer to the highest point, way, or level reached by a celestial body on its daily apparent path around a given point of observation. For example, the position of the Sun can be described as being at its zenith when it is at its highest point in the sky. In a figurative sense, zenith can also refer to the highest point of achievement. The word "zenith" comes from an inaccurate reading of the Arabic expression "samt al-ras," meaning "direction of the head" or "path above the head," by Medieval Latin scribes in the Middle Ages.