A regular stopper-knot, which prevents the rope from running out of retaining devices. One of the four basic maritime knots. The Figure-8 knot doesn’t jam even under great strain and can be released effortlessly. Its only drawback is that without strain the knot may fall undone. The Figure-8 is an important sailing and climbing knot.
ABoK #420, #520, #570
Pass the running end under the standing part to make a loop.
Then pass it over the standing part and through the loop from beneath.
Tighten the knot.
The Figure-8 knot is complete.