What does "billfish" mean?

Billfish: A name applied to several distinct fishes: (a) The garfish (Tylosurus, or Belone, longirostris) and allied species. (b) The saury, a slender fish of the Atlantic coast (Scomberesox saurus). (c) The Tetrapturus albidus, a large oceanic species related to the swordfish; the spearfish. (d) The American fresh-water garpike (Lepidosteus osseus).