![cover image](https://wikiwandv2-19431.kxcdn.com/_next/image?url=https://upload.wikimedia.org/wikipedia/commons/thumb/b/b3/Geometrie_carre.png/640px-Geometrie_carre.png&w=640&q=50)
Side
line segment joining two adjacent vertices in a polygon or polytope / From Wikipedia, the free encyclopedia
In geometry, a side is a straight line that is part of a shape. A shape made of straight lines is called a polygon. The number of sides on a polygon can be written as .
![Thumb image](http://upload.wikimedia.org/wikipedia/commons/thumb/b/b3/Geometrie_carre.png/320px-Geometrie_carre.png)
A side can also mean the face of a 3D shape. A 3D shape made of flat faces is called a polyhedron. The number of faces on a polyhedron can be written as .[1][2][3]
As an example, the square on the right has four sides. The sides in this picture are made with black straight lines. The four sides are:
- the black straight line from A to B
- the black straight line from B to C
- the black straight line from C to D
- the black straight line from D to A