submarine

Everyday

1. A submarine is a ship that can travel under the water as well as on top of it. tree →
2. (adjective, formal) Submarine means under the sea: "submarine cables". tree →
3. (USA) A submarine sandwich (a sub) is a long bread roll filled with meat, cheese and salad. tree →

In the lessons

In science, submarines fill tanks with water to sink and blow the water out with air to rise — this shows floating and sinking. In stories and history, submarines are used for exploring and in wars. Phrases: nuclear submarine, yellow submarine, submarine sandwich, by submarine.

Examples

• The submarine dived deep under the ocean. tree →
• A submarine fills its tanks with water to sink. tree →
• Sailors on a submarine use a periscope to see above the water. tree →
• Submarine cables carry the internet under the sea. tree →
• I ordered a turkey submarine for lunch. tree →
• The submarine travelled 300 kilometres in 10 hours, so 30 kilometres an hour. tree →

Note

Countable. Short form: sub. The prefix sub- means under (subway, submerge). "Underwater" is the everyday word for the adjective sense.