Ett nystan is a 'ball of yarn'. Att nysta is 'to wind up wool into a ball'. Garn is 'yarn'. Ullgarn or yllegarn is yarn from wool, bomullsgarn from cotton. Garn also means 'fishing net'.
Garn and yarn are related of course, and my etymological dictionary tells us that these two Germanic words have relatives in many other Indoeuropean languages, e.g. Latin hernia. The original meaning is 'snöre snott av torkade tarmar' - ''string twined by dried intestines'. Now can you feel the millennia rushing by!
PS: Also Greek khordé from which comes cord - 'musical string', catgut, also from intestines.