The Simple English Wikipedia has an article on: Brain Pronunciation enPR: brān, IPA (key): /breɪn/ Audio (US)(file) Audio (UK)(file) Noun Singular brain Plural brains (countable) Your brain is the part of your body that is inside your head. The brain is the part of the body that thinks and controls the rest of the body through the nervous system. He has serious brain damage from falling off of his bicycle and hitting his head. Wikiwand - on Seamless Wikipedia browsing. On steroids.