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]Bouvier's Law Dictionary, Revised 6th Ed (1856):
QUADRANS, civil law. The fourth part of the whole. Hence the heir exquadrante; that is to say, the fourth-part of the whole.