The Collaborative International Dictionary of English v.0.48:

Adminicle \Ad*min"i*cle\, n. [L. adminculum support, orig., that
   on which the hand rests; ad + manus hand + dim. ending
   -culym.]
   1. Help or support; an auxiliary. --Grote.
      [1913 Webster]

   2. (Law) Corroborative or explanatory proof.
      [1913 Webster]

   Note: In Scots law, any writing tending to establish the
         existence or terms of a lost deed. --Bell.
         [1913 Webster]

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

ADMINICLE 1. A term, in the Scotch and French law, for any writing or deed
referred to by a party, in an action at law, for proving his allegations. 2.
An ancient term for aid or support. 3. A term in the civil, law for
imperfect proof. Tech. Dict. h.t.; Merl. Repert. mot Adminicule.