ääripiste

Aäripiste is an Estonian term that translates roughly to "extremal point" or "edge point" and is used in several domains to denote a point located at the boundary or outermost limit of a set, shape, region, or data domain.

In mathematics, ääripunkt or ääripiste refers to an extreme point of a set. In convex analysis, an extreme point of a convex set is a point that cannot be expressed as a convex combination of two distinct points of the set. For polygons and polyhedra, many extreme points are vertices and define the hull of the figure. Extreme points are fundamental to representations of convex hulls and to optimization problems.

In geography and cartography, the term can describe points farthest in a given direction, such as the northernmost, southernmost, easternmost, or westernmost points of a country or region. These extremal points are used in border delineation, navigation, and geographic descriptions.

In other contexts, an ääripiste may denote a boundary point of a mathematical domain, a limit of a data set, or an edge pixel in image processing, depending on the field.

Etymology: derived from äär meaning border or edge and punkt meaning point, reflecting its core sense of a point at the boundary.

See also: boundary point, extreme value, vertex, convex hull, antipode.