A T-shirt (or tee shirt) is a shirt, usually buttonless, collarless, an pocketless, with a round neck and short sleeves, that is pulled on over the head and covers most of a person's torso. The sleeves of the T-shirt extend at least slightly over the shoulder but not completely over the elbow (in short-sleeve version). A shirt that is either longer or shorter than this ceases to be a T-shirt.