The word for which the pronoun stands is called its antecedent. It may be in the same sentence, in a previous sentence, or not given at all. An example would be The boy threw the football. He threw it over the fence. Boy is the antecedent for he, and football is the antecedent for it. A pronoun can be an antecedent for another pronoun. He likes his new car. He is the antecedent for his. The antecedent always comes before the pronoun for which it is the antecedent.
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from Daily Grammar Lessons Blog http://dailygrammarlessons.blogspot.com/2018/09/lesson-22-parts-of-speech-pronouns.html