What is the word for the noun that a pronoun is replacing?

The term for the noun that a pronoun replaces is known as the "antecedent." In grammar, an antecedent provides the context for the pronoun, allowing the reader or listener to understand to whom or what the pronoun refers. For example, in the sentence "Maria lost her keys," "Maria" is the antecedent of the pronoun "her." This linkage is essential for clarity in communication, as it avoids ambiguity and confusion about what the pronoun is indicating. The concept of the antecedent is vital for understanding pronoun usage and ensuring effective sentence construction in both spoken and written language.

The other terms, such as subject, object, and modifier, have specific grammatical roles that do not refer to the noun replaced by the pronoun, which is why they do not serve as the correct answer in this context.