Source : Webster's Revised Unabridged Dictionary (1913)

Digestion \Di*ges"tion\ (?; 106), n. [F. digestion, L.
   digestio.]
   1. The act or process of digesting; reduction to order;
      classification; thoughtful consideration.

   2. (Physiol.) The conversion of food, in the stomach and
      intestines, into soluble and diffusible products, capable
      of being absorbed by the blood.

   3. (Med.) Generation of pus; suppuration.

Source : WordNet®

digestion
     n 1: the process of decomposing organic matter (as in sewage) by
          bacteria or by chemical action or heat
     2: the organic process by which food is converted into
        substances that can be absorbed into the body
     3: learning and coming to understand ideas and information;
        "his appetite for facts was better than his digestion"