Swordfish, along with marlin, spearfish and sailfish are referred to as billfish. This refers to the sword-like projection of the upper jaw. Swordfish were first described by Aristotle who used the Greek word xiphias meaning "sword." The Romans used the term gladius which also meant "sword." The scientific name for swordfish, Xiphias gladius, is a combination of both names.
Shaped like an oversized mackerel, the body is thickest in the shoulder area, tapering to the tail which is reinforced by a keel on each side. They vary in color from deep brown to black on the back and upper surface of the body to almost white on the side and lower body. The long upper- jaw and snout form a flat, sharp double-edged sword which may be as much as one third the total length of the fish. They are large, aggressive fish sometimes reaching 14 feet in length and a weight of 1,200 pounds.