This paper defines concept of complete hypergraph, enumerates the number of hypergraphs constructed on any nonempty set and determine a lower bound for the number of all complete hypergraphs. We define an equivalence relation on hypergraphs, this relation establishes a connection between hypergraphs and graphs. Moreover, the concept of hypergraph is redefined via the concept of hypergroupoid and a connection between of hypergraphs and hypergroupoids was considered. Finally, we consider a relation between fundamental group and fundamental graph.