1. A pointed or rounded projection on the masticating surface of a tooth.

2. One of the flaps of a heart valve.

A pointed projection or peak created by the intersection of two arcs.

One of a series of low, crescent-shaped mounds of beach material separated by smoothly curved, shallow troughs spaced at more or less regular intervals along and generally perpendicular to the beach face. Also known as beach cusp.

Any of the funnel-shaped regions in the magnetosphere extending from the front magnetopause to the polar ionosphere, and filled with solar wind plasma.

A singular point of a curve at which the limits of the tangents of the portions of the curve on either side of the point coincide. Also known as spinode.