Source : Webster's Revised Unabridged Dictionary (1913)

Dephlegmation \De`phleg*ma"tion\, n. [Cf. F. d['e]flegmation.]
   (Chem.)
   The operation of separating water from spirits and acids, by
   evaporation or repeated distillation; -- called also
   {concentration}, especially when acids are the subject of it.
   [Obs.]