brain brain /ˈbreɪn/

noun

1. () That part of the central nervous system that includes all the higher nervous centers; enclosed within the skull; continuous with the spinal cord  ( encephalon , brain )
   that part of the central nervous system that includes all the higher nervous centers; enclosed within the skull; continuous with the spinal cord
    The brain is responsible for controlling all of our bodily functions
   The brain is responsible for controlling all of our bodily functions
   
   
2. () That which is responsible for one's thoughts, feelings, and conscious brain functions; the seat of the faculty of reason  ( nous , psyche , brain , head , mind )
   that which is responsible for one's thoughts, feelings, and conscious brain functions; the seat of the faculty of reason
    His mind wandered
   his mind wandered
    I couldn't get his words out of my head
   I couldn't get his words out of my head
   
   
3. () Mental ability  ( brainpower , learning ability , mental capacity , brain , mentality , wit , smarts [Informal, N. American, Australian] )
   mental ability
    He's got plenty of brains but no common sense
   he's got plenty of brains but no common sense
   
4. () Someone who has exceptional intellectual ability and originality  ( brainiac [ N. American] , Einstein , mastermind , brain , genius , brainbox [Informal, British] , smart cookie [Informal, N. American] )
   someone who has exceptional intellectual ability and originality
    Mozart was a child genius
   Mozart was a child genius
    He's smart but he's no Einstein
   he's smart but he's no Einstein
   
   
5. The brain of certain animals used as meat  ( brain )
   the brain of certain animals used as meat
    The butcher had lamb brain on sale.
   The butcher had lamb brain on sale.
   
   

verb

1. Kill by smashing someone's skull  ( brain )
   kill by smashing someone's skull
   
2. Hit on the head  ( brain )
   hit on the head