What is a Jumper?
In British English, a sweater may also be called a pullover, jumper or jersey. In the United States however, "jumper" refers to a style of women's sleeveless dress, worn over a blouse or shirt, and "jersey" refers to a knit shirt, especially if part of an athletic uniform. In India sleeveless jacket with zipper is call jumper.
Jersey vs Jerseys (jumper)
It was so popular that men were banned from knitting in Jersey during the peak fishing season of August to September. Because of the popularity of Jersey wool, knitted jumpers came to be called jerseys, after the island, the first recording of a jumper being called a jersey is in 1837.