The height of prosperity or success; the peak period when something is at its most vigorous.
その企業は設立から十年目に全盛を迎えた。
The company reached its heyday in its tenth year after being founded.
彼は全盛期に多くのヒット曲を出した。
He released many hit songs during his prime.
昭和の映画産業の全盛を懐かしむ人がいる。
Some people nostalgically remember the heyday of the film industry in the Showa era.