Vocabulary - The Edge

The connections between vertices are called Edges. An edge connects Vertex $u$ to Vertex $v$.

In the map example, a road between two cities is an edge. In social networks, a friendship is an edge. In chemistry, a bond between atoms is an edge.

Edges can carry extra information like weight (distance, cost, time) or direction. Problems often give you a list of edges: "There is an edge between $1$ and $2$, between $2$ and $3$." You will learn to store these efficiently. The number of edges $E$ affects algorithm speed.