Definition of "Peak" :
noun: a brim that projects to the front to shade the eyes
noun: the top or extreme point of something (usually a mountain or hill)
"The view from the peak was magnificent."
noun: the highest point (of something)
"At the peak of the pyramid."
noun: the most extreme possible amount or value
noun: a V shape
noun: the highest level or degree attainable; the highest stage of development
"The peak of perfection."
noun: the period of greatest prosperity or productivity
verb: to reach the highest point; attain maximum intensity, activity
"That wild, speculative spirit peaked in 1929."