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3 definitions found

From: Webster's Revised Unabridged Dictionary (1913)

 Dis·til·la·tion n.
 1. The act of falling in drops, or the act of pouring out in drops.
 2. That which falls in drops. [R.]
 3. Chem. The separation of the volatile parts of a substance from the more fixed; specifically, the operation of driving off gas or vapor from volatile liquids or solids, by heat in a retort or still, and the condensation of the products as far as possible by a cool receiver, alembic, or condenser; rectification; vaporization; condensation; as, the distillation of illuminating gas and coal, of alcohol from sour mash, or of boric acid in steam.
 Note:The evaporation of water, its condensation into clouds, and its precipitation as rain, dew, frost, snow, or hail, is an illustration of natural distillation.
 4. The substance extracted by distilling.
 Destructive distillation Chem., the distillation, especially of complex solid substances, so that the ultimate constituents are separated or evolved in new compounds, -- usually requiring a high degree of heat; as, the destructive distillation of soft coal or of wood.
 Dry distillation, the distillation of substances by themselves, or without the addition of water or of other volatile solvent; as, the dry distillation of citric acid.
 Fractional distillation. Chem. See under Fractional.
 

From: Webster's Revised Unabridged Dictionary (1913)

 Frac·tion·al a.
 1. Of or pertaining to fractions or a fraction; constituting a fraction; as, fractional numbers.
 2. Relatively small; inconsiderable; insignificant; as, a fractional part of the population.
 Fractional crystallization Chem., a process of gradual and approximate purification and separation, by means of repeated solution and crystallization therefrom.
 Fractional currency, small coin, or paper notes, in circulation, of less value than the monetary unit.
 Fractional distillation Chem., a process of distillation so conducted that a mixture of liquids, differing considerably from each other in their boiling points, can be separated into its constituents.
 

From: WordNet (r) 2.0

 fractional distillation
      n : fractionation of a liquid by distillation