Also known as a "nodes", the points specifically used to describe a polygon or polyline in a "vector" or "linestring" representation.
In geometry, a vertex (plural vertices) is a special kind of point which describes the corners or intersections of geometric shapes. Vertices are commonly used in computer graphics to define the corners of surfaces (typically triangles) in 3D models, where each such point is given as a vector.
Source: wiki.gis.com
Also see Wikipedia.
