Source : Webster's Revised Unabridged Dictionary (1913)

Intumescence \In`tu*mes"cence\, n. [Cf. F. intumescence.]
   1. The act or process of swelling or enlarging; also, the
      state of being swollen; expansion; tumidity; especially,
      the swelling up of bodies under the action of heat.

            The intumescence of nations.          --Johnson.

   2. Anything swollen or enlarged, as a tumor.

Source : WordNet®

intumescence
     n 1: swelling up with blood or other fluids (as with congestion)
          [syn: {intumescency}]
     2: the swelling of certain substances when they are heated
        (often accompanied by release of water) [syn: {intumescency},
         {swelling}]