Skein may refer to: A flock of geese or ducks in flight A wound ball of yarn with a centre pull strand; see Hank A metal piece fitted over the end of a wagon axle, to which the wheel is mounted Skein (unit), a unit of length used by weavers and tailors Skein dubh, a Scottish knife Skein (fish), the egg sack of the fish eggs and/or the eggs themselves Skein module, a mathematical concept Skein relation, a mathematical concept often used to give a simple definition of knot polynomials Skein (comics), a fictional supervillain in the Marvel Comics universe Skein (hash function), a candidate hash function to the NIST hash function competition from Bruce Schneier et al. See also The Tangled Skein, a novel by Baroness Orczy With a Tangled Skein, a novel by Piers Anthony, book three of Incarnations of Immortality Skien