背(せ)びれ

せびれ
noun
dorsal fin
natureanimal-fish
1. dorsal fin
The fin located on the back of a fish or marine animal. Also written as 背鰭(せびれ) with kanji. The dorsal fin helps with stability and, in some species, serves as a defense mechanism.
サメの背(せ)びれが水面(すいめん)に見(み)えた。
A shark's dorsal fin was visible above the water.
この魚(さかな)は背(せ)びれに毒(どく)がある。
This fish has venom in its dorsal fin.
イルカの背(せ)びれの形(かたち)は個体(こたい)ごとに異(こと)なり、識別(しきべつ)に使(つか)われる。
The shape of a dolphin's dorsal fin differs by individual and is used for identification.

Also written with kanji as 背鰭(せびれ), though the hiragana form 背(せ)びれ is more common in general writing since 鰭(ひれ) is an uncommon kanji. Part of a set of fin terms using ～ひれ/～びれ.

Related fin terms

  • 胸(むな)びれ: pectoral fin
  • 腹(はら)びれ: pelvic/ventral fin
  • 尾(お)びれ: caudal/tail fin
  • 尻(しり)びれ: anal fin

Common collocations

Related Words

Related: 尾(お)びれ (caudal/tail fin)
general
Added 2026.3.31 4:14 · Revised 2026.9.2 13:02
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