##### Wiktionary

**graph theory**

n. (context mathematics English) The study of the properties of graphs (in the sense of sets of vertices and sets of ordered or unordered pairs of vertices).

##### Wikipedia

**Graph theory**

In mathematics **graph theory** is the study of * graphs*, which are mathematical structures used to model pairwise relations between objects. A graph in this context is made up of * vertices*, *nodes*, or *points* which are connected by *edges*, *arcs*, or *lines*. A graph may be *undirected*, meaning that there is no distinction between the two vertices associated with each edge, or its edges may be * directed* from one vertex to another; see Graph (discrete mathematics) for more detailed definitions and for other variations in the types of graph that are commonly considered. Graphs are one of the prime objects of study in discrete mathematics.

Refer to the glossary of graph theory for basic definitions in graph theory.