The Collaborative International Dictionary of English v.0.48:

Antecedence \An`te*ced"ence\, n.
   1. The act or state of going before in time; precedence. --H.
      Spenser.
      [1913 Webster]

   2. (Astron.) An apparent motion of a planet toward the west;
      retrogradation.
      [1913 Webster]

WordNet (r) 3.0 (2006):

antecedence
    n 1: preceding in time [syn: priority, antecedence,
         antecedency, anteriority, precedence, precedency]
         [ant: posteriority, subsequence, subsequentness]