The Collaborative International Dictionary of English v.0.48:

Delegacy \Del`e*ga*cy\, n. [From Delegate, a.]
   1. The act of delegating, or state of being delegated;
      deputed power. [Obs.]
      [1913 Webster]

            By way of delegacy or grand commission. --Sir W.
                                                  Raleigh.
      [1913 Webster]

   2. A body of delegates or commissioners; a delegation. [Obs.]
      --Burton.
      [1913 Webster]

WordNet (r) 3.0 (2006):

delegacy
    n 1: the state of serving as an official and authorized delegate
         or agent [syn: representation, delegacy, agency]
    2: a group of representatives or delegates [syn: deputation,
       commission, delegation, delegacy, mission]
    3: the appointment of a delegate