Source : Webster's Revised Unabridged Dictionary (1913)

Pyroxylin \Py*rox"y*lin\, n. (Chem.)
   A substance resembling gun cotton in composition and
   properties, but distinct in that it is more highly nitrified
   and is soluble in alcohol, ether, etc.; -- called also
   {pyroxyle}.

Source : WordNet®

pyroxylin
     n : highly flammable nitrocellulose used in making collodion and
         plastics and lacquers [syn: {pyroxyline}]