The Collaborative International Dictionary of English v.0.48:

Nuncius \Nun"ci*us\, n.; pl. Nuncii. [L.] (Roman & Old Eng.
   Law)
      (a) A messenger.
      (b) The information communicated.
          [1913 Webster]

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

NUNCIUS, international law, A messenger, a minister; the pope's legate,
commonly called a nuncio. It is used to express that a will or testament.
has been made verbally, and not in writing, Vide Testament nuncupative;
Will, nuncupative; 1 Williams on Exec. 59; Swinb. Index, h.t.; Ayl. Pand.
359; 1 Bro. Civ. Law, 288; Roberts on Wills, h.t.; 4 Kent, Com. 504; 2
Bouv. Inst. n. 436.