Definition of 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.
(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.