billfish /ˈbɪlˌfɪʃ/ noun6 •Any of several fish, of the families Istiophoridae and Xiphiidae, that have an elongated jaw.Collectively, the billfishes are among the most sought-after game fishes because of their grace and power, in and out of the water. — 1983 •Other fish with elongated jaws. •gars (Lepisosteidae spp.) •sauries (Scomberesocidae spp.) •silver gar (Strongylura maritima, in family Belonidae) •northern pipefish (Syngnathus fuscus, in family Syngnathidae) formsbillfishes