dorsal fin
Refers to the fin on the back of fish and some marine mammals.
The shark's dorsal fin is sticking out of the water.
この魚は背びれが長くて美しい。
This fish has a long, beautiful dorsal fin.
Standard kanji spelling for 'dorsal fin'.
Mixed kanji-kana spelling, common in everyday writing.
Kana spelling, used when the kanji 鰭 is considered difficult or in children's materials.
Compound of 背 (se, 'back') and 鰭 (hire, 'fin'), with rendaku voicing of hire to bire.