A pronoun is a word that represents a noun or refers to someone or something without using a noun. Pronouns can refer to people, things, concepts, or places and are used in sentences to avoid repeating nouns. Common pronouns include he, she, they, we, it, this, that, and pronouns can be seen in example sentences such as "Jacob is my friend, he is handsome" and "Princess is my classmate, she is smart."