Source : Webster's Revised Unabridged Dictionary (1913)

Mayhem \May"hem\, n. [The same as maim. See {Maim}.] (Law)
   The maiming of a person by depriving him of the use of any of
   his members which are necessary for defense or protection.
   See {Maim}.

Source : WordNet®

mayhem
     n 1: the willful and unlawful crippling or mutilation of another
          person
     2: violent and needless disturbance [syn: {havoc}]