Definition:Polygon/Adjacent

Definition
Each vertex of a polygon is formed by the intersection of two sides.

The two sides that form a particular vertex are referred to as the adjacents of that vertex, or described as adjacent to that vertex.

Similarly, each side of a polygon intersects two other sides, and so is terminated at either endpoint by two vertices.

The two vertices that terminate a particular side are referred to as the adjacents of that side, or described as adjacent to that side.

Similarly, those two vertices are described as adjacent to each other.

Finally, two sides of a polygon that meet at the same vertex are adjacent to each other.