* Pronoun: A pronoun is a word that replaces a noun (or noun phrase). They are used to avoid repetition and make language more concise. Examples include: I, you, he, she, it, we, they, me, him, her, etc.
* Proper Noun: A proper noun is the name of a specific person, place, or thing. They are always capitalized. Examples include: John, London, Earth, Amazon River.
Key Difference: Pronouns refer to something already mentioned, while proper nouns are unique identifiers.
Let me know if you have any more questions about grammar!