Meaning

noun that part of the central nervous system that includes all the higher nervous centers; enclosed within the skull; continuous with the spinal cord

noun mental ability

noun that which is responsible for one's thoughts and feelings; the seat of the faculty of reason

originEtymology tree Proto-Germanic *bragną Proto-West Germanic *bragn Old English bræġn Middle English brayn English brain Inherited from Middle English brayn, from Old English bræġn, from Proto-West Germanic *bragn, from Proto-Germanic *bragną. Cognate with Scots braine, brane (“brain”), North Frisian brayen, brein, Brain (“brain”), Saterland Frisian Brainge, Bräienge (“brain”), West Frisian brein…

Etymology from Wiktionary, CC BY-SA 3.0