antecedent (n .) Look up antecedent at Dictionary.com
late 14c. in grammar ("noun to which a pronoun refers") and in logic ("if A is, then B is;" A is the antecedent, B the consequent), from Old French antecedent (14c.) or directly from Latin antecedentem (nominative antecedens), noun use of present participle of antecedere "go before, precede," from ante "before" (see ante-) + cedere "to yield" (see cede).

Hence "an event upon which another follows" (1610s). As an adjective in English from c. 1400. Related: Antecedently.