The Collaborative International Dictionary of English v.0.48:

Tipstaff \Tip"staff`\, n.; pl. Tipstaff.
   1. A staff tipped with metal. --Bacon.
      [1913 Webster]

   2. An officer who bears a staff tipped with metal; a
      constable. --Macaulay.
      [1913 Webster]

WordNet (r) 3.0 (2006):

tipstaff
    n 1: staff with a metal tip carried as a sign of office by e.g.
         a bailiff or constable

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

TIPSTAFF. An officer appointed by the marshal of the court of king's bench,
to attend upon the judges with a kind of a rod or staff tipped with silver.
     2. In the United States, the courts sometimes appoint an officer who is
known by this name, whose duty it is to wait on the court and serve its
process.