peakn.[OE. pek, AS. peac, perh of Celtic origin; cf. Ir. peac a sharp-pointed thing. Cf. Pike.]1. A point; the sharp end or top of anything that terminates in a point; as, the peak, or front, of a cap.(Beau. & Fl.)2. The top, or one of the tops, of a hill, mountain, or range, ending in a point; often, the whole hill or mountain, esp. when isolated; as, the Peak of Teneriffe.()Silent upon a peak in Darien. (Keats.)3. (Naut.) The upper aftermost corner of a fore-and-aft sail; -- used in many combinations; as, peak-halyards, peak-brails, etc.()Fore peak. (Naut.) See under Fore.()v. i.1. To rise or extend into a peak or point; to form, or appear as, a peak.()There peaketh up a mighty high mount. (Holand.)2. To achieve a maximum of numerical value, intensity of activity, popularity, or other characteristic, followed by a decline; as, the stock market peaked in January; his performance as a pitcher peaked in 1990; sales of the XTX model peaked at 20,000 per year.()3. To acquire sharpness of figure or features; hence, to look thin or sickly.(Shak.)[Cf. Peek.]4. To pry; to peep slyly.(Shak.)Peak arch (Arch.), a pointed or Gothic arch.()v. t. (Naut.) To raise to a position perpendicular, or more nearly so; as, to peak oars, to hold them upright; to peak a gaff or yard, to set it nearer the perpendicular.()