What does "toggle" mean?

Toggle: (Mach.) Two rods or plates connected by a toggle joint. Toggle iron, a harpoon with a pivoted crosspiece in a mortise near the point to prevent it from being drawn out when a whale, shark, or other animal, is harpooned. -- Toggle joint, an elbow or knee joint, consisting of two bars so connected that they may be brought quite or nearly into a straight line, and made to produce great endwise pressure, when any force is applied to bring them into this position.