In mathematics, a link is a collection of knots which may be linked (or knotted) together.
More formally, a link is a subspace of 3-dimensional Euclidean space (or often the 3-sphere) whose connected components are homeomorphic to circles. A knot can be described as a link with one component. Links and knots are studied in a branch of mathematics called knot theory.
The simplest nontrivial example of a link with more than one component is called the Hopf link, which consists of two circles (or unknots) linked together once. Borromean rings form a link with three components each equivalent to the unknot.
See also