资料来源 : Webster's Revised Unabridged Dictionary (1913)

Extraction \Ex*trac"tion\, n. [Cf. F. extraction.]
   1. The act of extracting, or drawing out; as, the extraction
      of a tooth, of a bone or an arrow from the body, of a
      stump from earth, of a passage from a book, of an essence
      or tincture.

   2. Derivation from a stock or family; lineage; descent;
      birth; the stock from which one has descended. ``A family
      of ancient extraction.'' --Clarendon.

   3. That which is extracted; extract; essence.

            They [books] do preserve as in a vial the purest
            efficacy and extraction of that living intellect
            that bred them.                       --Milton.

   {The extraction of roots}. (Math.)
      (a) The operation of finding the root of a given number or
          quantity.
      (b) The method or rule by which the operation is
          performed; evolution.