Brain
noun
The kanji and the word are exactly the same. That means they share meanings as well.
The reading is the same as what you learned with the kanji. Don't have to use your brain for that.
アイツは本当に脳が弱いよな。
He has no brains.
ちょっとは脳を使って考えろよ！
Use your brain when you think!
この国の人たちは脳を食べるってこと、知ってる？珍味なんだよ。
Did you know that people eat brains in this country? It’s a delicacy.