What does 彗星 mean?
彗星 is a Japanese noun meaning “comet” in English. It is written as 彗星 in kanji, すいせい in hiragana, and suisei in romaji. This word is part of JLPT N2 vocabulary.
Example sentence
そういう方法で彼はその彗星を発見したのです。
That's how he discovered the comet.