潜水艦（せんすいかん、sensuikaん）
- submarine

The Japanese word 潜水艦 （潜水艦） means "submarine." It refers to a type of naval vessel that is capable of operating underwater. These vessels are used for various purposes, including military operations, scientific research, and exploration. The word describes the entire vessel, not just a part of it. The word also encompasses all types of submarines.

⚫︎潜水艦が海に潜った。 Translation: The submarine submerged into the sea. ⚫︎その国は最新の潜水艦を開発した。 Translation: That country developed a state-of-the-art submarine.

You would use 潜水艦 （潜水艦） when talking about submarines in general or specific submarines. This word is appropriate in both formal and informal conversations. It's often used in news reports, discussions about military strategy, or when describing a scene in a movie or book involving a submarine.

潜水艦 （潜水艦） is typically written using the kanji 潜水艦. ⚫︎ The reading, せんすいかん, is in hiragana. ⚫︎ There are no other common ways to write this word. ⚫︎ The okurigana (送りがな, the hiragana attached to kanji) is consistent.

There are no direct synonyms in Japanese, but you might use phrases to describe a submarine.

There aren't specific antonyms, as the word refers to a type of vessel. You could consider "surface vessel" or "ship" as a broad contrast.

日本は最新の技術を駆使して、高性能な《潜水艦を建造した。》 ・Translation: Japan built a high-performance submarine utilizing the latest technology. ・Explanation: This sentence describes Japan's ability to build cutting-edge submarines, highlighting their advanced technology.

その《潜水艦は、敵のレーダーから隠れるために、深く潜航した。》 ・Translation: That submarine submerged deeply to hide from the enemy's radar. ・Explanation: This sentence describes the action of a submarine using its ability to dive to avoid detection.

The word 潜水艦 （潜水艦） is a compound word: ⚫︎潜水, sensui, meaning "submerging" or "diving." The kanji 潜 means "to submerge" or "to dive," and 水 means "water." ⚫︎艦, kan, meaning "warship" or "vessel." This kanji is typically used for larger naval ships. So, the literal translation is something like "diving vessel" or "submerging warship," which accurately describes its function.