teredo

n. (pl. -s) bivalve mollusc that bores into submerged timbers of ships etc. [latin from greek]

n. A genus of long, slender, wormlike bivalve mollusks which bore into submerged wood, such as the piles of wharves, bottoms of ships, etc.; -- called also shipworm. See Shipworm. See Illust. in App.