Merriam-Webster's defines "pronouns" as:
plural pronouns : any of a small set of words (such as I, she, he, you, it, we, or they) in a language that are used as substitutes for nouns or noun phrases and whose referents are named or understood in the context
Here are some examples of pronouns:
Sporty Spice likes playing sports. Sometimes she plays baseball with her friend Nomar Garciaparra. He is one of 13 players in Major League history to hit two grand slams during a single game, and the only player to achieve the feat at his home stadium. Sometimes after they play baseball they drink Pepsi.