A cardigan is a special type of sweater with a characteristic unusual shape. Instead of being a pullover sweater that goes over the top of the head, a cardigan opens in the front, which allows you to pull on it like a jacket. A traditional cardigan has buttons up the middle, but other types have hook closures or simply stay open. You can wear this versatile type of sweater under suits for formal outfits or pair it with jeans and a T-shirt for a casual look. Cardigans are of all styles and shapes. There are long-sleeved and short-sleeved ones, and you can even find cropped styles that end mid-chest or long style that reaches the knee.