U-boat

/ˌju ˈboʊt/

Other forms: U-boats

A U-boat was a type of submarine used in World War I and II by Germany. In 1915, a German U-boat famously sunk the RMS Lusitania, an unarmed ship full of civilians.

U-boat is an Anglicized form of the German U-Boot, shorthand for Unterseeboot, or "undersea boat." During both World Wars, U-boats carried torpedoes and fought the armed ships belonging to Allied navies. They were also used to block the shipping routes of Germany's enemies. U-boats were fast and sturdy, and they moved efficiently above the surface as well as underwater.

Definitions of U-boat

1. noun

   a submersible warship usually armed with torpedoes
   synonyms: pigboat, sub, submarine

   types:

   attack submarine

   a military submarine designed and armed to attack enemy shipping

   auxiliary research submarine

   a submarine for research purposes

   fleet ballistic missile submarine

   a submarine carrying ballistic missiles

   nautilus, nuclear submarine, nuclear-powered submarine

   a submarine that is propelled by nuclear power

   type of:

   submersible, submersible warship

   a warship designed to operate under water