acme
n.n. the highest point of quality or the best possible state of something. It is a very formal word that people usually use in serious writing or when talking about history.
n. the highest point of development or perfection; the peak of a curve or the apex of a hierarchy. Often used in historical or formal contexts to describe the zenith of a civilization or a specific period.
The golden age of the empire was its acme.
Historians often debate whether the Renaissance was the acme of human achievement or merely a brief period of artistic growth.
The philosopher argued that the acme of human reason was not found in the pursuit of power, but in the quiet contemplation of nature's laws.
Directly borrowed from Ancient Greek ἀκμή (akmḗ, “point, high point”).