A T-shirt is a lightweight knit shirt, usually with a crew neck and sleeves which reach above the elbow. They are generally long enough to reach down to the waist. A simple design, with the sleeves sewn onto the body, the T-shirt gets its name from being shaped like a "T" when fully spread out. They can be found in white and other colors, as well as with innumerable designs and slogans.
T-shirts are casual, everyday clothing, and, as such, are ubiquitous in western society. Being cheap and fairly easily customizable, T-shirts are a popular means of expressing views. They are also heavily used to advertise: corporate logo T-shirts are very common, and most tourist attractions sell T-shirts advertising themselves.