fractionation

from WordNet (r) 3.0 (2006)

fractionation
    n 1: a process that uses heat to separate a substance into its
         components [syn: {fractionation}, {fractional process}]
    2: separation into portions

from The Collaborative International Dictionary of English v.0.48

fractionation \frac`tion*a"tion\ n.
   the act or process of separating a mixture into portions of
   different composition, as in distillation or {fractional
   crystallization}.

   Syn: fractional process.
        [WordNet 1.5 +PJC]

   2. (Petroleum industry) Separation of crude oil into
      components of differing composition by {fractional
      distillation}.
      [PJC]