海豚

Native formation, attested abundantly in the Classical era. Also 海豨 (hǎixī, literally “sea-pig”), 江豚 (jiāngtún, literally “river-pig”). Semantically compare English mereswine (“porpoise or dolphin”, literally “sea-pig”).

海豚

1. dolphin

Unclear. One of the more likely native-Japanese theories is that this was originally a compound of Old Japanese elements 魚 (iwo, “fish”) +‎ 食 (uka, “food, something used as food”).

/iwo uka/ → /iru uka/ → /iruka/

Another possibility is that it was a borrowing from Ainu. Compare Sakhalin Ainu リク (riku), イリク (iriku), or Kuril Ainu リカ (rika, “whale”).[1] Given the unlikely sound shift required for the Old Japanese derivation, an origin from Ainu seems more likely.

The spelling 海豚, which literally means “sea pig”, is an orthographic borrowing from Chinese.

• (Irregular reading)
• (Tokyo) いるか [ìrúká] (Heiban – [0])[2][3]
• IPA^(key): [iɾɯ̟ᵝka̠]

海豚(いるか) • (iruka) 

1. a dolphin or porpoise (the mammal)

As with many terms that name organisms, this term is often spelled in katakana, especially in biological contexts (where katakana is customary), as イルカ.

• 鱪(しいら) (shīra), 鱰(しいら) (shīra): a dolphin fish, a dorado fish

• 1988, 国語大辞典（新装版） (Kokugo Dai Jiten, Revised Edition) (in Japanese), Tōkyō: Shogakukan

From Middle Chinese 海豚 (xoj^X dwon, literally “sea pig”). Cognate with Okinawan 海豚 (fītu).

海豚 (hiragana ふぃとぅ, romaji fitu, hiragana ぴとぅ, romaji pitu)

1. dolphin

From Middle Chinese 海豚 (xoj^X dwon, literally “sea pig”). Cognate with Okinawan 海豚 (fītu).

海豚 (hiragana ひーとぅい, romaji hītui)

1. dolphin

From Middle Chinese 海豚 (xoj^X dwon, literally “sea + pig”). Cognate with Okinawan 海豚 (fītu).

海豚 (hiragana ふとぅ, romaji futu)

1. dolphin

From Middle Chinese 海豚 (xoj^X dwon, literally “sea pig”).

海豚 (hiragana ふぃーとぅ, romaji fītu)

1. dolphin

From Middle Chinese 海豚 (xoj^X dwon, literally “sea pig”). Cognate with Okinawan 海豚 (fītu).

海豚 (hiragana ふとぅ, romaji futu)

1. dolphin