Cow
Bull, Ox
noun
The kanji and the word are the same. This word is a bit broader than cow though, and can also be used to be bull and ox.
Since this word is made up of a single kanji, it uses the kun'yomi reading. Here's a mnemonic to help you to remember it:
You're leading the cows around the field. To get them to move, you yell out "USH, USH, USH!" (うし) because you have a speech impediment and want to say "MUSH MUSH MUSH." Go ahead and say this out loud, yelling it if you can.
牛がたくさんいますね。
There are many cows.
牛のステーキとチキンステーキ、どっちがいい？
Which would you like, a beef steak or a chicken steak?
うちのペットは牛です。
My pet is a cow.