A T-shirt is a casual shirt that typically has short sleeves, a round neckline, and no collar. It is usually made of a light, breathable fabric such as cotton and is designed to be worn as a standalone garment or as an undershirt. T-shirts come in a variety of colors, patterns, and designs, and are a popular choice for casual wear in many countries around the world. The name "T-shirt" is derived from the shirt's T shape when viewed from the front, with the body and sleeves forming a straight line. T-shirts have become a fashion staple and are often used to express personal style, beliefs, and interests.