T-shirts are clothes that cover the torso of the human body and, depending of the type, parts of the arms. They are made from knitted fabrics. Like underwear, they are worn in direct contact with the skin. They may be used as underwear, but generally, they are used as outer clothing.
The name "T-shirts" refers to the T shape arrangement of the body and sleeves. T-shirts have no collar. Shirts similar to T-shirts, but with collar, are called polo shirts or polos.
Generally, T-shirts have short sleeves, but there are long-sleeve T-shirts, too. T-shirts may have round necks or V-necks. A special type of T-shirts, called henley shirts or henleys, has a placket beneath the neckline which is closed by buttons.
T-shirts may be unicolored, dyed in different colors, or printed with a logo, a message or an image.