0 the highest point reached by a heavenly body (= any object existing in space, especially a planet, or the sun) as it travels around, or appears to travel around, another body:
1 the best or most successful point or time:
In the 1860s, Tolstoy was at the zenith of his achievement.
2 the best, highest, or most successful point or time:
Their popularity reached its zenith in the mid-1990s.
The 1970s were the period when the generation of archaeologists educated in the 1960s reached the zenith of their creativity.
At such points, the available light is contributed by a multitude of small openings in the canopy distributed over a wide range of zenith angles.
The discourse and discord came to its zenith with the 1967 war.
Three decades on from its creative zenith, so-called 'progressive' rock remains probably the most critically maligned and misunderstood genre in the history of rock music.
The sun was then truly at its zenith.
This underlying sense of unease, then, finally reached its zenith towards the end of the 1970 courses.
The process of extending social insurance coverage reached its zenith in the early 1980s, when roughly 70 per cent of the labour force was protected.
This meeting indicates that sealing had already reached its zenith.