A knot is a method of fastening or securing linear material such as rope
A rope is a length of fibres, twisted or braided together to improve strength for pulling and connecting. It has tensile strength but is too flexible to provide compressive strength...

 by tying or interweaving. It may consist of a length of one or several segments of rope, string, webbing
Webbing is a strong fabric woven as a flat strip or tube of varying width and fibres often used in place of rope. The name webbing comes from the meshed material frequently used in its construction, which resembles a web...

, twine
Twine is a light string or strong thread composed of two or more smaller strands or yarns twisted together. More generally, the term can be applied to any thin cord....

, strap
A strap, sometimes also called strop, is an elongated flap or ribbon, usually of fabric or leather.Thin straps are used as part of clothing or baggage, or bedding such as a sleeping bag. See for example spaghetti strap, shoulder strap...

, or even chain
A chain is a sequence of connected links.Chain may also refer to:Chain may refer to:* Necklace - a jewelry which is worn around the neck* Mail , a type of armor made of interlocking chain links...

 interwoven such that the line can bind to itself or to some other object—the "load". Knots have been the subject of interest for their ancient origins, their common uses, and the area of mathematics known as knot theory
Knot theory
In topology, knot theory is the study of mathematical knots. While inspired by knots which appear in daily life in shoelaces and rope, a mathematician's knot differs in that the ends are joined together so that it cannot be undone. In precise mathematical language, a knot is an embedding of a...

There is a large variety of knots, each with properties that make it suitable for a range of tasks.