完全二分图是一种特殊的二分图，可以把图中的顶点分成两个集合，使得第一个集合中的所有顶点都与第二个集合中的所有顶点相连。

完全二分图是一个二分图，使得对于任何两个顶点和，都是中的一条边。且的完全二分图记为。

In the mathematical field of graph theory, a complete bipartite graph or biclique is a special kind of bipartite graph where every vertex of the first set is connected to every vertex of the second set.

Graph theory itself is typically dated as beginning with Leonhard Euler's 1736 work on the Seven Bridges of Königsberg. However, drawings of complete bipartite graphs were already printed as early as 1669, in connection with an edition of the works of Ramon Llull edited by Athanasius Kircher. Llull himself had made similar drawings of complete graphs three centuries earlier.