Translation

The Japanese word for "Bull" is oushi 牡牛.

  • Bull vs. Steer, Ox
    A Bull is a male Cattle that has not been castrated, while Steer and Ox are castrated. In Japanese, the term kyoseigyuu 去勢牛 refers to them.
Romaji o u shi
Hiragana
Katakana
Kanji
Meaning Male Cow
School Level 小2

Loan-word

The word "Bull" katakanized would be buru ブル.
Romaji bu ru
Katakana
Hiragana

Further Reading

Wikipedia: Bull (牡牛)
Bulldog.