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

"Voltage peak."

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."