What is "dephlegmation"

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.

n. (context chemistry obsolete English) The operation of separate water from spirits and acids, by evaporation or repeated distillation; concentration.