A pronoun is a word that functions as a noun and that can substitute for another noun or noun phrase in a sentence. Pronouns tend to be short words like “I,” “we,” “him,” “she,” “that,” “it,” and “none,” but some pronouns are longer like “himself,” “something,” “neither,” and “everybody.”
When we first introduce a person or thing into a conversation or text, we tend to say the name of exactly what or whom we are talking about. We might say “My aunt is in the hospital,” but if we want to continue talking about our aunt, we do not have to keep repeating “my aunt,” “my aunt,” “my aunt.” Instead, we can just call her “she.” Pronouns are particularly convenient when the thing they substitute for is very long as in, say, “the jar at the back of the refrigerator on the left next to the mustard.” We can say that whole string of words just once and then call that particular jar “it” from then on.
Pronouns often substitute for specific nouns that are already mentioned or are about to be mentioned in a particular conversation or piece of text, but sometimes they stand for certain abstract, nominal ideas. For example, the pronoun “nobody” in the sentence “Nobody in the room said a word,” refers to the idea of no person at all or no particular person. The pronouns “everything,” “anyone,” “whatever,” “which,” and “nothing” are a few more examples of pronouns that are not used to substitute for particular things or people but are used to refer to abstract ideas having to do with people, places, and things.
Pronouns are also used when the thing or person being referred to is obvious from the context. One might see someone on the bus who is smiling broadly to himself and comment to your friend, “Well, he looks happy!”