Fur, Hair
noun
The kanji and the word are exactly the same. That means they share meanings as well.
け
Since this word is made up of a single kanji, it should use the kun'yomi reading. When learning the kanji, you didn't learn that reading, so here's a mnemonic to help you with this word: Look down! You're holding something covered in fur. It's a furry kettle (け)! It's the weirdest kettle you've ever seen, but presumably it keeps the water hot for much longer.
この牛、毛がたくさんですね。
This cow has a lot of hair.
生まれたときから毛がありました。
I had hair since I was born.
犬の毛のせいで白のシャツはきれないんです。
I can't wear a white shirt because of the dog fur.