A knot is an intentional complication in cordage which may be useful or decorative. Practical knots may be classified as hitches, bends, splices, or knots. Knots are used in navigation, mountaineering, decoration and other arts. A knot in the strictest sense serves as a stopper or knob at the end of a rope to keep that end from slipping through a grommet or eye. 

Technique: From ancient times knots have always been used in very different ways (simple knots, bows, hanging knots, terry knots, scuff knots, etc.) and applications. Basically, knots have a fundamentally practical utility especially in hazardous environments such as mountain, sea, etc. The rope technique distinguishes three main applications for knots: tying some ends together, tying an object to a fix place and mooring, linking two objects together. Strength, security slipping, and capsizing are the main properties of knots. 

Materials: ropes, laces and cables made of natural fibres or synthetical materials could be used for knot tying. Noble materials such as linen, cotton, gold and silver cord are also used for decorative tying purposes.