Source : Webster's Revised Unabridged Dictionary (1913)

Accessary \Ac*ces"sa*ry\ (277), n.; pl. {Accessaries}. [Cf.
   {Accessory} and LL. accessarius.] (Law)
   One who, not being present, contributes as an assistant or
   instigator to the commission of an offense.

   {Accessary before the fact} (Law), one who commands or
      counsels an offense, not being present at its commission.
      

   {Accessary after the fact}, one who, after an offense,
      assists or shelters the offender, not being present at the
      commission of the offense.

   Note: This word, as used in law, is spelt accessory by
         Blackstone and many others; but in this sense is spelt
         accessary by Bouvier, Burrill, Burns, Whishaw, Dane,
         and the Penny Cyclopedia; while in other senses it is
         spelt accessory. In recent text-books on criminal law
         the distinction is not preserved, the spelling being
         either accessary or accessory.