The Collaborative International Dictionary of English v.0.48:

mutation \mu*ta"tion\ (m[-u]*t[=a]"sh[u^]n), n. [L. mutatio, fr.
   mutare to change: cf. F. mutation. See Mutable.]
   Change; alteration, either in form or qualities.
   [1913 Webster]

         The vicissitude or mutations in the superior globe are
         no fit matter for this present argument. --Bacon.
   [1913 Webster]

   2. (Biol.) Gradual definitely tending variation, such as may
      be observed in a group of organisms in the fossils of
      successive geological levels.
      [Webster 1913 Suppl.]

   3. (Biol.)
      (a) As now employed (first by de Vries), a cellular
          process resulting in a sudden inheritable variation
          (the offspring differing from its parents in some
          well-marked character or characters) as distinguished
          from a gradual variation in which the new characters
          become fully developed only in the course of many
          generations. The occurrence of mutations, the
          selection of strains carrying mutations permitting
          enhanced survival under prevailing conditions, and the
          mechanism of hereditary of the characters so
          appearing, are well-established facts; whether and to
          what extent the mutation process has played the most
          important part in the evolution of the existing
          species and other groups of organisms is an unresolved
          question.
      (b) The result of the above process; a suddenly produced
          variation.

   Note: Mutations can occur by a change in the fundamental
         coding sequence of the hereditary material, which in
         most organisms is DNA, but in some viruses is RNA. It
         can also occur by rearrangement of an organism's
         chromosomes. Specific mutations due to a change in DNA
         sequence have been recognized as causing certain
         specific hereditary diseases. Certain processes which
         produce variation in the genotype of an organism, such
         as sexual mixing of chromosomes in offspring, or
         artificially induced recombination or introduction of
         novel genetic material into an organism, are not
         referred to as mutation.
         [Webster 1913 Suppl. +PJC]

   4. (Biol.) a variant strain of an organism in which the
      hereditary variant property is caused by a mutation[3].
      [Webster 1913 Suppl.]

WordNet (r) 3.0 (2006):

mutation
    n 1: (biology) an organism that has characteristics resulting
         from chromosomal alteration [syn: mutant, mutation,
         variation, sport]
    2: (genetics) any event that changes genetic structure; any
       alteration in the inherited nucleic acid sequence of the
       genotype of an organism [syn: mutation, genetic mutation,
       chromosomal mutation]
    3: a change or alteration in form or qualities

Moby Thesaurus II by Grady Ward, 1.0:

64 Moby Thesaurus words for "mutation":
   ablaut, acoustic phonetics, alteration, altering, anomaly,
   articulatory phonetics, avatar, betacism, catabolism, catalysis,
   change, changing, consubstantiation, departure, deviant, deviation,
   displacement, evolution, evolving, gradation, heterotopia,
   innovation, metabolism, metagenesis, metamorphism, metamorphosing,
   metamorphosis, metastasis, metathesis, metempsychosis,
   modification, modifying, morphophonemics, mutant, mutated form,
   novelty, orthoepy, permutation, phonetics, phonology,
   reincarnation, rhotacism, sound shift, sport, transanimation,
   transfiguration, transfigurement, transformation, transforming,
   transformism, translation, translocation, transmigration,
   transmogrification, transmutation, transmuting, transposition,
   transubstantiation, turn, umlaut, variant, variation, varying,
   vicissitude



Bouvier's Law Dictionary, Revised 6th Ed (1856):

MUTATION, French law. This term is synonymous with change, and is
particularly applied to designate the change which takes place in the
property of a thing in its transmission from one person to another;
permutation therefore happens when, the owner of the thing sells, exchanges
or gives it. It is nearly synonymous with transfer. (q.v.) Merl. Repert.
h.t.