A long coil of yarn or hair intended for weaving, dyeing, or heat setting. Yarn sold in skeins often needs to be re-wound into spools or balls using a swift depending on the application. A skein is not a specific unit of length.
The flight of a flock of undomesticated fowl such as wild mallards or wild geese
Skein relation, a mathematical concept often used to give a simple definition of knot polynomials