Graphite

from WordNet (r) 3.0 (2006)

graphite
    n 1: used as a lubricant and as a moderator in nuclear reactors
         [syn: {graphite}, {black lead}, {plumbago}]

from The Collaborative International Dictionary of English v.0.48

Graphite \Graph"ite\, n. [Gr. gra`fein to write: cf. F.
   graphite. See {Graphic}.] (Min.)
   Native carbon in hexagonal crystals, also foliated or
   granular massive, of black color and metallic luster, and so
   soft as to leave a trace on paper. It is used for pencils
   (improperly called lead pencils), for crucibles, and as a
   lubricator, etc. Often called {plumbago} or {black lead}.
   [1913 Webster]

   {Graphite battery} (Elec.), a voltaic battery consisting of
      zinc and carbon in sulphuric acid, or other exciting
      liquid.
      [1913 Webster]