A sweater vest, also known as a sleeveless sweater and tank top or sleeveless jumper (UK), is an item of knitwear that is similar to a sweater, but without sleeves. They were popular in the 20th century, particularly in the 1970s in the UK, and are again growing in popularity in this century.[2]
The name "tank top", recorded in English since 1968, derives from its resemblance to a tank suit, a style of one-piece women's swimsuit with shoulder straps, so called since the 1920s, because it was worn in a "swimming tank", an obsolete term for a swimming pool. In American English, a tank top refers to a sleeveless shirt (what in British English would usually be called a vest).