peak

(noun): A point; the sharp end or top of anything that terminates in a point; as, the peak, or front, of a cap.
(noun): The highest value reached by some quantity in a time period.
(noun): The top, or one of the tops, of a hill, mountain, or range, ending in a point.
(noun): The whole hill or mountain, especially when isolated.
(noun): The upper aftermost corner of a fore-and-aft sail.
(noun): The narrow part of a vessel's bow, or the hold within it.
(noun): The extremity of an anchor fluke; the bill.
(noun): A local maximum of a function, e.g. for sine waves, each point at which the value of y is at its maximum.
(verb): To reach a highest degree or maximum.
(verb): To rise or extend into a peak or point; to form, or appear as, a peak.
(verb): To raise the point of (a gaff) closer to perpendicular.
(adjective): Maximal, maximally quintessential or representative; constituting the culmination of
(adjective): Bad
(adjective): Unlucky; unfortunate

The stock market reached a peak in September 1929.
They reached the peak after 8 hours of climbing.
peak-brails
Historians argue about when the Roman Empire began to peak and ultimately decay.