degree

The degree of a node v of a graph G is the number of graph edges which touch v.

directed graph

A graph in which every edge is associated with an ordered pair of nodes. Also called an oriented graph. See also directed link.

directed link

A link with a direction that starts at one of its incident nodes and ends at the other incident node. Directed links are usually drawn with arrowheads that indicate the direction. In a mathematical sense, a directed link is an ordered pair of nodes, while an undirected link is an unordered pair of nodes. See also directed graph.

disconnected graph

A graph containing at least two nodes that are not linked by a path. In the following graph, node 5 is not linked by a path to any other node. Nodes 3 and 4 are not linked by a path to any nodes other than nodes 3 and 4.