A casual shirt is a type of clothing that is comfortable and informal. It can come in many different styles, such as a TEE, KNIT, or POLO. A TEE is a short-sleeved shirt with a round neckline, usually made of cotton or polyester. A KNIT shirt is a type of shirt that is knitted from yarn or thread, often with a collar and buttons. A POLO shirt is a type of shirt with a collar, short sleeves, and a placket with two or three buttons. All of these types of shirts are considered casual and are perfect for everyday wear.