 Mester means master ; it may have been deemed Mester Stoor Worm because it was the " master and father of all <unk> " . In Scotland worm may frequently be applied to a dragon , as it is in northern England according to folklorist Katharine Briggs , a usage that derives from the Saxon and Norse terms . The spelling of the Old English and obsolete variant of the word worm is wyrm , meaning dragon or serpent . Traill Dennison 's definition gives <unk> as " superior " with stoor being " large , powerful , strong or stern " . He describes worm as " any animal of serpent shape " . 
