It's all in the details. When it comes to a henley shirt, the details may be small, just two to five buttons, but what a difference they make. That's what makes up a henley, those characteristic buttons, a pullover collarless neckline, and a placket of about three to five inches. A placket is the double layers of fabric that hold the buttons and buttonholes of a shirt, like found in the cuffs of button-up long-sleeve shirts.
A henley falls right in between a traditional tee and a formal collared button-up shirt. It's still considered casual, but those little details bump up this look. Its closest cousin is a polo shirt, but there's no confusing the two. A henley is typically more campfire casual, less boardroom basic.
While the traditional henley is best known as a long-sleeve shirt, the look is also available in a short-sleeve tee, too. Wear it long, keep it short, a henley shirt will keep your look cool, comfortable and casual.