A pronoun is a word that replaces a noun in a sentence. Pronouns are used so that our language is not cumbersome with the same nouns being repeated over and over in a paragraph. Some examples of pronouns include I, me, mine, myself, she, her, hers, herself, we, us, ours and ourselves. You may have noticed that they tend to come in sets of four, all referring to the same person, group or thing.
•He, him, his and himself, for example, all refer to a male person or something belonging to him
•They, them, theirs and themselves all refer to a group or something belonging to a group, and so on.
The truth is that there are many different types of pronouns, each serving a different purpose in a sentence.