Translation

The Japanese word for "Otter" is kawa-uso カワウソ.

Romaji ka wa u so
Hiragana
Katakana
Kanji
Meaning River Otter
School Level 小1

Loan-word

The word "Otter" katakanized would be ottā オッター.
Romaji o ttaa
Katakana
Hiragana

Synonyms

Lutrinae.

Further Reading

Wikipedia: Otter ()