Definition:Polygon/Adjacent/Vertices

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

Those two vertices are described as adjacent to each other.

Also known as
Adjacent vertices (in a polygon) are also known as consecutive vertices or consecutive angles.

The term adjacent angles can also be seen, but as this is used for a different concept, it is preferred that it is not used in this context.