stoor worm

The story

The first element may be stoor, stour (“large, stout”) (cognate to Old Norse stórr), or it may be from Old Norse Storðar-gandr (literally “world-monster”), an alternative name for Jörmungandr, from poetic use of storð to mean "earth", whence storðar men, "earth's necklace", i.e. "sea" (storð more often meant "wood" and storðar-gandr more often meant "wood's bane" i.e. "fire"). The second element is worm (“sea-dragon”).