any wormlike marine bivalve mollusc of the genus Teredo and related genera and family Teredinidae. They bore into wooden piers, ships, etc, by means of drill-like shell valves
See also piddock
shipworm in American English
(ˈʃɪpˌwɜrm)
noun
any of a family (Teredinidae) of marine, bivalve mollusks with wormlike bodies: theyburrow into and damage submerged wood, as of ships, pilings, etc.