Table 1.

Basic graphical network terminology

Term	Definition
Node	An entity in the network that is capable of interacting with other entities
Edge	The interactions or relationships between nodes
Degree	The number of edges a node is connected to
Directed network	A network in which edges only can go in one direction (e.g., A > B is different from B > A)
Undirected network	A network in which edges are not directed (e.g., A-B implies that A and B are equal interactors)
Centrality	A measure of node importance, which can be determined using several different metrics, generally in some way describes the number of paths in the network that pass through a node or how many other nodes it is connected to.
Adjacency matrix	A matrix representation of a graphical network in which the values of the entries represent the interactions or relationships between nodes. The size of the matrix is n by n, where n is the total number of nodes in the network.

Table defining general terminology used to describe graphical network methods.