From Pathfinder Wiki
|Tying the Overhand Knot|
Use: one of the most fundamental knots and forms the basis of many others including the simple noose, overhand loop, angler's loop, reef knot, fisherman's knot and water knot. The overhand knot is very secure, and can jam badly, so only use if you want a permanent knot. It is often used to prevent the end of a rope or string from unraveling.