彗星は英語で
comet

英語の定義

彗星
1. n. (astronomy) comet

comet
1. 名詞. 彗星。ほうきぼし。氷と塵を主成分とし、太陽に近づくと揮発したガスからなる大気状の部分（コマ）や尾を生じる小天体。

comet
1. n. (astronomy) A celestial body consisting mainly of ice, dust and gas in a (usually very eccentric) orbit around the Sun and having a "tail" of matter blown back from it by the solar wind as it approach
2. n. A celestial phenomenon with the appearance given by the orbiting celestial body.
3. n. Any of several species of hummingbird found in the Andes.