The Collaborative International Dictionary of English v.0.48:

Coral \Cor"al\, n. [Of. coral, F, corail, L. corallum, coralium,
   fr. Gr. kora`llion.]
   1. (Zool.) The hard parts or skeleton of various Anthozoa,
      and of a few Hydrozoa. Similar structures are also formed
      by some Bryozoa.
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   Note: The large stony corals forming coral reefs belong to
         various genera of Madreporaria, and to the hydroid
         genus, Millepora. The red coral, used in jewelry, is
         the stony axis of the stem of a gorgonian (Corallium
         rubrum) found chiefly in the Mediterranean. The fan
         corals, plume corals, and sea feathers are species
         of Gorgoniacea, in which the axis is horny.
         Organ-pipe coral is formed by the genus Tubipora, an
         Alcyonarian, and black coral is in part the axis of
         species of the genus Antipathes. See Anthozoa,
         Madrepora.
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   2. The ovaries of a cooked lobster; -- so called from their
      color.
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   3. A piece of coral, usually fitted with small bells and
      other appurtenances, used by children as a plaything.
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   Brain coral, or Brain stone coral. See under Brain.

   Chain coral. See under Chain.

   Coral animal (Zool.), one of the polyps by which corals are
      formed. They are often very erroneously called coral
      insects.

   Coral fish. See in the Vocabulary.

   Coral reefs (Phys. Geog.), reefs, often of great extent,
      made up chiefly of fragments of corals, coral sands, and
      the solid limestone resulting from their consolidation.
      They are classed as fringing reefs, when they border the
      land; barrier reefs, when separated from the shore by a
      broad belt of water; atolls, when they constitute
      separate islands, usually inclosing a lagoon. See Atoll.


   Coral root (Bot.), a genus (Corallorhiza) of orchideous
      plants, of a yellowish or brownish red color, parasitic on
      roots of other plants, and having curious jointed or
      knotted roots not unlike some kinds of coral. See Illust.
      under Coralloid.

   Coral snake. (Zo)
      (a) A small, venomous, Brazilian snake (Elaps
          corallinus), coral-red, with black bands.
      (b) A small, harmless, South American snake (Tortrix
          scytale).

   Coral tree (Bot.), a tropical, leguminous plant, of several
      species, with showy, scarlet blossoms and coral-red seeds.
      The best known is Erythrina Corallodendron.

   Coral wood, a hard, red cabinet wood. --McElrath.
      [1913 Webster]

The Collaborative International Dictionary of English v.0.48:

Brain \Brain\ (br[=a]n), n. [OE. brain, brein, AS. bragen,
   br[ae]gen; akin to LG. br[aum]gen, bregen, D. brein, and
   perh. to Gr. bre`gma, brechmo`s, the upper part of head, if
   [beta] = [phi]. [root]95.]
   [1913 Webster]
   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.
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   Note: 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.
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   2. (Zool.) The anterior or cephalic ganglion in insects and
      other invertebrates.
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   3. The organ or seat of intellect; hence, the understanding;
      as, use your brains. " My brain is too dull." --Sir W.
      Scott.
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   Note: In this sense, often used in the plural.
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   4. The affections; fancy; imagination. [R.] --Shak.
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   5. a very intelligent person. [informal]
      [PJC]

   6. the controlling electronic mechanism for a robot, guided
      missile, computer, or other device exhibiting some degree
      of self-regulation. [informal]
      [PJC]

   To have on the brain, to have constantly in one's thoughts,
      as a sort of monomania. [Low]

   no-brainer a decision requiring little or no thought; an
      obvious choice. [slang]
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   Brain box or Brain case, the bony or cartilaginous case
      inclosing the brain.

   Brain coral, Brain stone coral (Zool.), 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
      M[ae]andrina 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 gland.
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WordNet (r) 3.0 (2006):

brain coral
    n 1: massive reef-building coral having a convoluted and
         furrowed surface