The correct answer is "A word that takes the place of another pronoun or noun." This is because a pronoun is a type of word that is used to replace a noun in a sentence. It helps to avoid repetition and make sentences more concise. Pronouns can refer to people, places, things, or ideas, and examples include "he," "she," "it," "they," and "this." So, the answer accurately defines a pronoun as a word that substitutes for another pronoun or noun.