Tail
noun
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. You haven't learned this reading yet though, so here's a mnemonic to help you:
You look down and you've sprouted a tail! You're so shocked that all you can say is "Oh. (お) Oh okay..." This your life now. A life with a tail.
コウイチは、魚の尾を見ただけで魚の種類を言うのが特技です。
Koichi can look at a fish's tail and tell you what kind it is based on that alone.
尾が無いと、鳥は上手く着りく出来ません。
Without tails, birds would have difficulty landing.
どうして犬の尾を短くする習慣が産まれたのでしょうか。
Why do you think the custom of shortening dog’s tails started?