Source : Webster's Revised Unabridged Dictionary (1913)

Incombustible \In`com*bus"ti*ble\, a. [Pref. in- not +
   combustible: cf. F. incombustible.]
   Not combustible; not capable of being burned, decomposed, or
   consumed by fire; uninflammable; as, asbestus is an
   incombustible substance; carbon dioxide is an incombustible
   gas.

   {Incombustible cloth}, a tissue of amianthus or asbestus;
      also, a fabric imbued with an incombustible substance. --
      {In`com*bus"ti*ble*ness}, n. -- {In`com*bus"ti*bly}, adv.