The Collaborative International Dictionary of English v.0.48:

Quadrans \Quad"rans\, n.; pl. Quadrantes. [L.]
   1. (Rom. Antiq.) A fourth part of the coin called an as. See
      3d As, 2.
      [1913 Webster]

   2. The fourth of a penny; a farthing. See Cur.
      [1913 Webster]