The Collaborative International Dictionary of English v.0.48:

Mutual \Mu"tu*al\, a. [F. mutuel, L. mutuus, orig., exchanged,
   borrowed, lent; akin to mutare to change. See Mutable.]
   1. Reciprocally acting or related; reciprocally receiving and
      giving; reciprocally given and received; reciprocal;
      interchanged; as, a mutual love, advantage, assistance,
      aversion, etc.
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            Conspiracy and mutual promise.        --Sir T. More.
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            Happy in our mutual help,
            And mutual love.                      --Milton.
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            A certain shyness on such subjects, which was mutual
            between the sisters.                  --G. Eliot.
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   2. Possessed, experienced, or done by two or more persons or
      things at the same time; common; joint; as, mutual
      happiness; a mutual effort. --Burke.
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            A vast accession of misery and woe from the mutual
            weeping, and wailing, and gnashing of teeth.
                                                  --Bentley.
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   Note: This use of mutual as synonymous with common is
         inconsistent with the idea of interchange, or
         reciprocal relation, which properly belongs to it; but
         the word has been so used by many writers of high
         authority. The present tendency is toward a careful
         discrimination.
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               Mutual, as Johnson will tell us, means something
               reciprocal, a giving and taking. How could people
               have mutual ancestors?             --P. Harrison.
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   Mutual insurance, agreement among a number of persons to
      insure each other against loss, as by fire, death, or
      accident.

   Mutual insurance company, one which does a business of
      insurance on the mutual principle, the policy holders
      sharing losses and profits pro rata.
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   Syn: Reciprocal; interchanged; common.
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