bipartite graph

in graph theory, a bipartite graph is a graph whose set of vertices is split into two, and no two vertices in the same group are directly connected.

in fancy words, a bipartite graph is a graph in which the vertex set can be partitioned into two sets, W and X, so that no two vertices in W share a common edge, and no two vertices in X share a common edge.

by the way a bipartite graph can also be defined as a graph with a chromatic number of 2
by the definition of chromatic number, a graph is $n$ chromatic

complete bipartite graph

a complete bipartite graph is actually not a complete graph

a complete bipartite graph with the vertices of sets $A$ and $B$ is depicted as $K_{A,B}$