Definition:Multigraph/Multiple Edge

Definition
Let $G = \left({V, E}\right)$ be a multigraph.

A multiple edge is an edge of $G$ which has another edge with the same endvertices.

That is, where there is more than one edge that joins any pair of vertices, each of those edges is called a multiple edge.

Also see

 * Definition:Simple Edge
 * Definition:Parallel Edges