Wiktionary
graph state
n. (context physics English) Any of a class of multipartite entangled quantum states that can be interpreted using the mathematics of graph theory
Wikipedia
Graph state
In quantum computing, a graph state is a special type of multi- qubit state that can be represented by a graph. Each qubit is represented by a vertex of the graph, and there is an edge between every interacting pair of qubits. In particular, they are a convenient way of representing certain types of entangled states.
Graph states are useful in quantum error-correcting codes, entanglement measurement and purification and for characterization of computational resources in measurement based quantum computing models.