Definition:Polygon/Vertex

Definition

 * IrregularPolygon.png

A corner of a polygon is known as a vertex.

Thus, in the polygon above, the vertices are $A, B, C, D$ and $E$.

Linguistic Note
The plural of vertex is vertices.

The word vertex is Latin for peak, from which the irregular plural form

Also defined as
Euclid, in, uses the term vertex to mean the corner of a polygon furthest up the page from the base.



Also see

 * Definition:Height of Polygon


 * Definition:Apex of Triangle

Note
The vertices and the sizes of the internal angles of those vertices are frequently referred to by the same letter.

Thus the angle of vertex $A$ is called angle $A$ and denoted $\angle A$.

This is considered by some to be an abuse of notation but its convenience outweighs its disadvantages.