A button-down collar is a type of shirt collar that features small buttons on the collar points, securing them to the shirt. This design helps keep the collar in place, providing a neat and tidy appearance. Button-down collars are commonly found on both casual and formal shirts, making them versatile for various occasions. Originally popularized by Polo Ralph Lauren in the 19th century, button-down collars were inspired by the collars worn by polo players to prevent flapping during matches. Today, they are a staple in men's and women's fashion, often associated with a smart-casual style.