Sound
Noise
noun, suffix
The kanji and the word are exactly the same. That means they share meanings as well.
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:
Did you hear that sound? It's barely audible (おと). Go ahead and say the word "audible" with the pronunciation of おと to help you to remember this.
これはフェラーリのエンジンの音だ。
This is the sound of a Ferrari engine.
上のフロアから、大きな音がしました。
There was a loud noise from the floor above.
雨の音がうるさくて、よく休めませんでした。
The sound of the rain was so loud I couldn't rest well.