noun
Refers to the fin of a fish or other aquatic animal. The reading はた is obsolete.
魚のひれが水の中で動いている。
The fish's fins are moving in the water.
サメの背びれが海面に出ている。
The shark's dorsal fin is sticking out of the water.
Kanji form; rarely used in modern writing.
Native Japanese word. The historical derivation is uncertain.