brain
nounThat soft whitish mass, or viscus, inclosed in the cranium or skull, in which the nerves and spinal marrow terminate, and which is supposed to be the seat of the soul or intelligent principle in man. It is divided above into a right and left hemisphere, and below into six lobes. It is composed of a cortical substance, which is external, and a medullary, which is internal. From the brain proceed nine pair of nerves, which are distributed principally to the head and neck.