[vimeo 39741097 w=500 h=281]
Terminal Vertices of a Path from Matt Swift on Vimeo.
A path may be infinite, but a finite path always has a first vertex, called its start vertex, and a last vertex, called its end vertex. Both of them are called terminal vertices of the path. The other vertices in the path are internal vertices. A cycle is a path such that the start vertex and end vertex are the same. The choice of the start vertex in a cycle is arbitrary.