Fisherman's knot

Canonical Name: fisherman's knot.
Variant Names: true lover's knot, waterman's knot, angler's knot, englishman's knot

Category: bend.
Origin: Ancient.
Related knots: overhand knot
Releasing: Jamming.
Efficiency: Unknown%..
Caveat:
Uses: Securing two lines, especially fiddly threads.
Comments: This is a great knot for tying threads or lines that are too thin for anything complicated. All you need to be able to do is tie an overhand knot in one end, pass the other end through it, and tie another one. Note that the first overhand can be tightened before the second is addressed, which stops the ends from flapping around. It is commonly used to tie fishing lines, and is popular because it can be tied in the most fiddly materials with cold wet hands, and because it crushes down to a very small blob which won't jam on a fishing rod. Once tight, the loose ends can be cropped very close to the knot.

If you are tying it in a mono-filament, such as a fishing line, the heat generated by the bending of the line into the very tight curves of the overhand knots can seriously weaken the line! If the line is wetted before the knot is tightened, it helps to dissipate the heat.
Structure: Consists of two overhand knots wrapped around each other that when pulled together collapse into one strong knot.
Tying: article/pictures