Wiktionary
strongly connected component
n. (context graph theory English) Given a directed graph, a maximal strongly connected subgraph.
Wikipedia
Strongly connected component
In the mathematical theory of directed graphs, a graph is said to be strongly connected if every vertex is reachable from every other vertex. The strongly connected components of an arbitrary directed graph form a partition into subgraphs that are themselves strongly connected. It is possible to test the strong connectivity of a graph, or to find its strongly connected components, in linear time.