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.