The Collaborative International Dictionary of English v.0.48:

Milled \Milled\ (m[i^]ld), a.
   1. Having been subjected to some process of milling.
      [1913 Webster]

   2. Specifically: Having multiple fine grooves on the rim, in
      the direction from obverse to reverse; -- of coins. Coins
      of silver and gold were milled to make it impossible for
      uncrupulous persons to shave small pieces from the edge
      without detection.
      [PJC]

   Milled cloth, cloth that has been beaten in a fulling mill.


   Milled lead, lead rolled into sheets.
      [1913 Webster]