zenith

n. point in sky directly overhead; peak, highest point; climax

In broad terms, the zenith is the direction pointing directly above a particular location (perpendicular, orthogonal). Since the concept of being above is itself somewhat vague, scientists define the zenith in more rigorous terms. Specifically, in astronomy, geophysics and related sciences (e.g., meteorology), the zenith at a given point is the local vertical direction pointing away from direction of the force of gravity at that location.
See more at Wikipedia.org...

Le Zénith is the name of a number of famous concert venues in France. There are 13 such halls located in Caen, Clermond Ferrand, Dijon, Lille, Montpellier, Nancy, Nantes, Orléans, Paris, Pau, Rouen, Toulon, and Toulouse.Anywhere but Home, the live CD and DVD kit by Evanescence as well as the Hullabaloo Soundtrack CD2 and DVD by English band Muse were recorded at Le Zénith in Paris. In March of 2005 Italian singer Laura Pausini held two concerts which would later appear on her live CD/DVD Live in Paris 05
See more at Wikipedia.org...

Noun
1. the point above the observer that is directly opposite the nadir on the imaginary sphere against which celestial bodies appear to be projected
(antonym) nadir
(hypernym) celestial point
(part-holonym) celestial sphere, sphere, empyrean, firmament, heavens, vault of heaven, welkin

n. zenith, meridian, acme

(n.)
That point in the visible celestial hemisphere which is vertical to the spectator; the point of the heavens directly overhead; -- opposed to nadir.
  

(n.)
hence, figuratively, the point of culmination; the greatest height; the height of success or prosperity.