antecedent
     adj : preceding in time or order [syn: {preceding}] [ant: {subsequent}]
     n 1: someone from whom you are descended (but usually more remote
          than a grandparent) [syn: {ancestor}, {ascendant}, {ascendent},
           {root}] [ant: {descendant}]
     2: a preceding occurrence or cause or event
     3: anything that precedes something similar in time;
        "phrenology was an antecedent of modern neuroscience"
        [syn: {forerunner}]
     4: the referent of an anaphor; a phrase or clause that is
        referred to by an anaphoric pronoun
Source: WordNet® 2.0