Lampreys /ˈlæmpriz/ (sometimes inaccurately called lamprey eels) are an ancient extant lineage of jawless fish of the order Petromyzontiformes /ˌpɛtroʊmɪˈzɒntɪfɔːrmiːz/, placed in the superclass Cyclostomata. The adult lamprey may be characterized by a toothed, funnel-like sucking mouth. The common name "lamprey" is probably derived from Latin lampetra, which may mean "stone licker" (lambere "to lick" + petra "stone"), though the etymology is uncertain. The plural form lamprey is sometimes seen.