A sweater with an open front fastened by buttons or a zipper is generally called a cardigan, but the nomenclature for other styles in different dialects can be quite confusing. In British English, a sweater may also be called a pullover, jumper or jersey. In the US however, "jumper" refers to a style of women's sleeveless dress, and "jersey" refers to a knit shirt, especially if part of an athletic uniform. If sleeveless, such a garment may be called a tank top in British English, while "tank top" in US English refers to a sleeveless shirt or undershirt. In the US and in Australian English, a sleeveless sweater may also be called a sweater vest, especially if it has a V-neck and somewhat formal appearance resembling a formal vest, a garment known as a waistcoat in the UK. In British English, "vest" refers to an undershirt. In South African English, a sweater is always called a jersey. In the sport of ice hockey, the top of a hockey player's uniform had traditionally been a sweater; and even though modern hockey uniform tops are more commonly a jersey they are typically referred to as a hockey sweater, regardless of the style.
Source:
http://en.wikipedia.org/wiki/Sweater
