Brain (?), v. t. [imp. & p.
p. Brained (?); p. pr. & vb. n.
1. To dash out the brains of; to kill by beating
out the brains. Hence, Fig.: To destroy; to put an end to; to
There thou mayst brain him.
It was the swift celerity of the death . . .
That brained my purpose.
2. To conceive; to understand. [Obs.]
?T is still a dream, or else such stuff as madmen
Tongue, and brain not.
Brain (?), n. [OE. brain,
brein, AS. bragen, brægen; akin to LG.
brägen, bregen, D. brein, and perh. to Gr. ?,
the upper part of head, if ? =?. √95.]
1. (Anat.) The whitish mass of soft matter
(the center of the nervous system, and the seat of consciousness and
volition) which is inclosed in the cartilaginous or bony cranium of
vertebrate animals. It is simply the anterior termination of the spinal
cord, and is developed from three embryonic vesicles, whose cavities are
connected with the central canal of the cord; the cavities of the vesicles
become the central cavities, or ventricles, and the walls thicken unequally
and become the three segments, the fore-, mid-, and hind-brain.
☞ In the brain of man the cerebral lobes, or largest part of the
forebrain, are enormously developed so as to overhang the cerebellum, the
great lobe of the hindbrain, and completely cover the lobes of the
midbrain. The surface of the cerebrum is divided into irregular ridges, or
convolutions, separated by grooves (the so-called fissures and sulci), and
the two hemispheres are connected at the bottom of the longitudinal fissure
by a great transverse band of nervous matter, the corpus callosum,
while the two halves of the cerebellum are connected on the under side of
the brain by the bridge, or pons Varolii.
2. (Zoöl.) The anterior or cephalic
ganglion in insects and other invertebrates.
3. The organ or seat of intellect; hence, the
understanding. " My brain is too dull." Sir W.
☞ In this sense, often used in the plural.
4. The affections; fancy; imagination. [R.]
To have on the brain, to have constantly in one's
thoughts, as a sort of monomania. [Low]
Brain box or case, the bony on
cartilaginous case inclosing the brain. -- Brain
coral, Brain stone coral (Zoöl),
a massive reef-building coral having the surface covered by ridges
separated by furrows so as to resemble somewhat the surface of the brain,
esp. such corals of the genera Mæandrina and
Diploria. -- Brain fag (Med.),
brain weariness. See Cerebropathy. -- Brain
fever (Med.), fever in which the brain is specially
affected; any acute cerebral affection attended by fever. --
Brain sand, calcareous matter found in the pineal