zenith

noun3

1. •
   The point in the sky vertically above a given position or observer; the point in the celestial sphere opposite the nadir.

   • 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[…] — 1638
2. •
   The highest point in the sky reached by a celestial body.

   • […] in the middle of the day, when the sun was in the zenith, the violence of the heat was too great to stir out […] — 1719
3. •
   Highest point or state; peak.

   • Winning the continental championship was the zenith of my career.