1. a warship designed to operate underwater
2. a large sandwich made with a long roll of bread
Usage: informal

1. existing, occurring, or used under the surface of the sea

Examples

• The submarine dove to a depth of 300 feet.
• Nuclear submarines can stay underwater for months.
• I ordered a turkey submarine for lunch.
• The deli makes the best submarine sandwiches in town.
• Scientists used a submarine cable to study the ocean floor.
• The submarine volcano erupted deep beneath the waves.
• Enemy submarines patrolled the waters during the war.