Source : Webster's Revised Unabridged Dictionary (1913)

Sailfish \Sail"fish\, n. (Zo["o]l.)
      (a) The banner fish, or spikefish ({Histiophorus}.)
      (b) The basking, or liver, shark.
      (c) The quillback.

Source : WordNet®

sailfish
     n 1: a saltwater fish with lean flesh
     2: large pelagic game fish having an elongated upper jaw and
        long sail-like dorsal fin
     [also: {sailfishes} (pl)]