Relating to something underwater; especially undersea: In the book Grace was reading, the pirates used a submarine cave to hide their loot!

1. A submersible vessel that operates underwater: A submarine is a navel U-boat that is usually armed with explosive devices or torpedoes.
2. A long marrow sandwich made of a crusty roll and cut lengthwise: Jane loved to eat submarines filled iwht meats, tomatoes, onions, and cheese.
3. In baseball, a pitch that is thrown with an underhand motion: Chuck was known for his submarines in playing baseball and was able to trick his opponents.

1. To serve or operate on a U-boat: When Jack was in the navy he submarined with others in the sub off the coast.
2. To attack, particularly to torpedo, with a U-boat: In the history book Jack was reading, the Germans submarined the Allies in the Second World War.
3. To deliver a ball using a low sidearm or underhand motion: Jim tried to submarine his pitch, but he was too nervous and bundled up his throw.
4. To move forward or even under in a sliding movement: When the car accident happened, little Susi submarined under the front seat because her safety belt broke.