sentences:  Naiads were associated with fresh water, as the Oceanids were with saltwater and the Nereids specifically with the Mediterranean, but because the ancient Greeks thought of the world's waters as all one system, which percolated in from the sea in deep cavernous spaces within the earth, there was some overlap.Arethusa, the nymph of a spring, could make her way through subterranean flows from the Peloponnesus to surface on the island of Sicily.The Greek word is Ναϊάς ("Nāïás", ), plural Ναϊάδες ("Nāïádes", ).