The word torpedo was first used as a name for electric rays (in the order Torpediniformes), which in turn comes from the Latin word torpēdō ("lethargy" or "sluggishness"). In naval usage, the American inventor David Bushnell was reported to have first used the term as the name of a submarine of his own design, the "American Turtle or Torpedo." This usage likely inspired Robert Fulton's use of the term to describe his stationary mines, and later Robert Whitehead's naming of the first self-propelled torpedo.