Definition:Connected (Graph Theory)

Vertices
Two vertices $u, v \in G$ are connected iff either:


 * $u = v$
 * $u \ne v$, and there exists a walk between them.

Graph
A graph is connected if every pair of vertices in $G$ is connected.

Otherwise, it is called disconnected.

Also see

 * $k$-Connected
 * Adjacent (Graph theory)