A weakly connected component of a simple directed graph (i.e., a digraph without loops) is a maximal subdigraph such that for every pair of distinct vertices u, v in the subdigraph, there is an undirected path from u to v. Weakly connected components can be found in the Wolfram Language using WeaklyConnectedGraphComponents[g].

connected component | directed graph | strongly connected component | weakly connected digraph

WeaklyConnectedGraphComponents