Source : Webster's Revised Unabridged Dictionary (1913)

Athanor \Ath"a*nor\, n. [F., fr. Ar. at-tann[=u]r, fr. Heb.
   tann[=u]r an oven or furnace.]
   A digesting furnace, formerly used by alchemists. It was so
   constructed as to maintain uniform and durable heat.
   --Chambers.

Source : WordNet®

athanor
     n : a self-feeding furnace that maintains a uniform temperature;
         used by alchemists