a two-edged ax, used anciently by the Amazons in fight; as also by the scamen, to cut adunder the ropes and cordage of the enemy's vessels. The bipennis was a weapon chiefly of the oriental nations, made like a double ax, or two axes joined back to back, with a short handle. Modern writers usually compare it to our halbard, or partisan; from which it differed in that it had no point, or that its shaft or handle was much shorter.