braid
A braid is a collection of lines or strings that are plaited together and whose ends are attached to two parallel straight lines. Braid theory was pioneered by the Austrian mathematician Emil Artin (1898–1962) and is related to knot theory. It also has other applications, for instance if we consider the way the roots of a polynomial move as one of the polynomial's coefficients changes, this motion can be thought of as a braid.