zenith

1. (astronomy) The point in the sky vertically above a given position or observer; the point in the celestial sphere opposite the nadir.Examples: "The 12 day wee had the wind high and large ſo that in two dayes ſaile we made the Sunne our Zenith or verticall point[…]"; "In this 10th m. appeared that prodigious Comett the tayl whereof was like the blade of a double edged sword, and reached almost from the horizon to the zenith."; "In the east a pillar of cloud reared from horizon to zenith, with a kind of arm outstretched like a threatening colossus."Antonyms: nadir, perigee

2. (astronomy) The highest point in the sky reached by a celestial body.Examples: "[…] in the middle of the day, when the sun was in the zenith, the violence of the heat was too great to stir out […]"; "As far to the west as Monica could see, her world was a sea of fog, […]. Above it arched a cerulean sky; as the sun climbed to the zenith, […], the fog gradually took on a bluish tinge."

3. (by extension) Highest point or state; peak.Examples: "Winning the continental championship was the zenith of my career."; "I find my zenith doth depend upon / A most auspicious star."; "It was during those civil troubles […] this aspiring family reached the zenith."Synonyms: acme, apogee, culmination, pinnacle, apexbroadly