We don't have synonyms for skain yet — it may be a rare, specialized, newly coined, or misspelled word. The closest thesaurus entries we have are skin, stain and skein.
(n) :
Obsolete spelling of skein. [A quantity of thread, yarn, etc., wound on a reel then removed and loosely knotted into an oblong shape; a skein of cotton is formed by eighty turns of thread around a reel with a fifty-four inch diameter.]
(n) :
Obsolete spelling of skein. [A quantity of thread, yarn, etc., wound on a reel then removed and loosely knotted into an oblong shape; a skein of cotton is formed by eighty turns of thread around a reel with a fifty-four inch diameter.]