A polygon is a closed shape formed by a finite number of non collinear line segments all lying on the same plane.

The line segments forming the polygon are called the sides of Polygon and each side intersects exactly two other sides only at their end points.

A polygon is a closed figure formed only by line segments. The sides of
each angle in a polygon are called the sides of the polygon, and the
vertex of each angle of the polygon is also known as a vertex of the
polygon. A Polygon is named after the letters corresponding to the vertices in consecutive order.

In the above diagram a six sided polygon known as a Hexagon is shown. The vertices of the Polygon ABCDEF are A, B, C, D, E and F. The sides of the polygon are

AB,

BC,

CD,

DE,

EF and

FA.

In general a polygon with n sides also have n vertices and n angles.