A sleeveless shirt, singlet or vest, also known as a wife-beater, yankton or tank top (USA), is a shirt manufactured without sleeves, or one whose sleeves have been cut off. Sleeveless shirts are worn by either sex, depending on the style. They are often worn by athletes in sports such as track and field and triathlon. Sleeveless shirts have been popular warm-weather casual wear in the United States since the 1970s,^{[citation needed]} and are regarded as acceptable public casual dress in most warm weather locales. They are mostly preferred in hot climates, since the arm holes provide ventilation and the thin fabric provides comfort.

In American English, a tank top is a sleeveless garment that can be worn by either sex. It is often worn under the shirt as underwear, although more colorful bright and well-designed tank tops are usually worn as an outer shirt. The term is also used in Australian English, although the term singlet is usually used to refer to the garment, which likewise is an unused term in American English. In British English, the term vest is used, while tank top refers to a sleeveless pullover. The name tank top, recorded in English since 1968, is derived from its resemblance to a tank suit, a style of one-piece women's swimsuit with shoulder straps. Its name derives from the 1920s term swimming tank, which is an obsolete term for what is now called a swimming pool. The tankini – a portmanteau of the words tank top and bikini – is a women's swimming version of the tank top.