In the mathematical theory of knots, a **flype** is a kind of manipulation of knot and link diagrams
used in the Tait flyping conjecture.
It consists of twisting a part of a knot, a tangle **T**, by 180 degrees. Flype comes from a Scots word meaning *to fold* or *to turn back* ("as with a sock").^{[1]}^{[2]} Two reduced alternating diagrams of an alternating link can be transformed to each other using flypes. This is the Tait flyping conjecture, proven in 1991 by Morwen Thistlethwaite and William Menasco.^{[3]}

- Reidemeister moves are another commonly studied kind of manipulation to knot diagrams.

**^**Hoste, Jim; Thistlethwaite, Morwen; Weeks, Jeff (1998), "The first 1,701,936 knots" (PDF),*The Mathematical Intelligencer*,**20**(4): 33–48, doi:10.1007/BF03025227, MR 1646740, archived from the original (PDF) on 2013-12-15. Tait used the term to mean, "a change of infinite complementary region").**^**Weisstein, Eric W. "Flype".*MathWorld*.**^**Weisstein, Eric W. "Tait's Knot Conjectures".*MathWorld*.