Definition of "Antecedent" :
noun: the referent of an anaphor; a phrase or clause that is referred to by an anaphoric pronoun
noun: a preceding occurrence or cause or event
noun: someone from whom you are descended (but usually more remote than a grandparent)
noun: anything that precedes something similar in time
"Phrenology was an antecedent of modern neuroscience."
adjective: preceding in time or order