A polo shirt, also called a golf shirt or tennis shirt, is a type of casual shirt that is typically made of cotton or a cotton blend. Polo shirts have a collar and a placket with two or three buttons at the top, and short sleeves. They are often associated with sports like golf and tennis, but they have become a popular casual wear option for men, women and kids. They come in various colors and designs, with or without a pocket, and with different collar styles.