A Peak

1. A point; the sharp end or top of anything that terminates in a point; as, the peak, or front, of a cap.
2. The highest value reached by some quantity in a time period.

Synonyms: apex, pinnacle

3. (geography) The top, or one of the tops, of a hill, mountain, or range, ending in a point.

Synonyms: summit, top

4. (geography) The whole hill or mountain, especially when isolated.
5. (nautical) The upper aftermost corner of a fore-and-aft sail.
6. (nautical) The narrow part of a vessel's bow, or the hold within it.
7. (nautical) The extremity of an anchor fluke; the bill.
8. (mathematics) A local maximum of a function, e.g. for sine waves, each point at which the value of y is at its maximum.