Source : Webster's Revised Unabridged Dictionary (1913)

Differentiation \Dif`fer*en`ti*a"tion\, n.
   1. The act of differentiating.

            Further investigation of the Sanskrit may lead to
            differentiation of the meaning of such of these
            roots as are real roots.              --J. Peile.

   2. (Logic) The act of distinguishing or describing a thing,
      by giving its different, or specific difference; exact
      definition or determination.

   3. (Biol.) The gradual formation or production of organs or
      parts by a process of evolution or development, as when
      the seed develops the root and the stem, the initial stem
      develops the leaf, branches, and flower buds; or in animal
      life, when the germ evolves the digestive and other organs
      and members, or when the animals as they advance in
      organization acquire special organs for specific purposes.

   4. (Metaph.) The supposed act or tendency in being of every
      kind, whether organic or inorganic, to assume or produce a
      more complex structure or functions.

Source : WordNet®

differentiation
     n 1: a discrimination between things as different and distinct;
          "it is necessary to make a distinction between love and
          infatuation" [syn: {distinction}]
     2: the mathematical process of obtaining the derivative of a
        function
     3: (biology) the structural adaptation of some body part for a
        particular function; "cell differentiation in the
        developing embryo" [syn: {specialization}, {specialisation}]