Clique number

The clique number of a graph is the size of the largest group of nodes where every node connects directly to every other node in that group. Think of it as the biggest "fully interconnected" team within a network. For example, if a group of friends all know each other directly, and this group is the largest such cluster in the network, the size of this group is the graph's clique number. It helps to measure the density of tightly connected subgroups within a larger network.