Relatedly, a person who is considered very smart can be called a brain. Used in a sentence: I have to study hard to do well in math, but my sister has brains and aces her tests without studying. This means they are smart and able to figure things out, especially difficult or complex problems. Real-life examples: You may have heard a person being described as having brains. This usage alludes to the brain being the organ that handles thinking. The plural form brains is used as a term for intelligence or intellect. Used in a sentence The brain is the most complex and perhaps the most studied organ. Your brain is very important and has a vast number of jobs, such as keeping all of your memories, telling your other organs what to do, and helping you read these words. Animals have brains too, although they aren’t capable of doing all of the things the human brain is able to do. Real-life examples: You and every other person have a brain. The brain, spinal cord, and nerves make up the nervous system. It is the seat of all your conscious thoughts and unconscious impulses and is like the control center of the body, allowing you to do things like speak, move your muscles, and breathe without thinking. Your brain is a squishy organ located inside your head and is protected by your skull. The word brain has several other senses as a noun and a few as a verb. The plural form brains refers to intelligence or a person who is the smartest member of a group. The brain is the organ in humans and animals that’s responsible for thought processes.