zenith
n. countablen. the highest point or the most successful time in someone's life or career. In science, it is the point in the sky directly above you.
n. the highest point reached by a celestial object or the time at which something is most powerful or successful. Often used metaphorically to describe the peak of a career or historical era.
The sun reaches its zenith at noon.
The Roman Empire reached its territorial zenith during the second century under the rule of Emperor Trajan.
Critics argue that the composer reached his creative zenith with his fifth symphony, a work that remains unsurpassed in its emotional depth and structural complexity.
From Middle English cenyth, from Medieval Latin cenit, from Arabic سَمْت (samt, “direction, path”), from the fuller form سَمْت اَلرَّأْس (samt ar-raʔs, “direction of the head”). The -ni- for -m- is sometimes thought to be due to a misreading of the three strokes, which is plausible, though it could be a mere phonetic approximation.
Often used with the definite article 'the' when referring to a specific peak or astronomical point.