Cotton is a type of fibre ( natural cellulose fibre) and jersey is a knitting technique.
Jersey is further divided into 2 ; single jersey and double jersey.Both are techniques of knitting. Generally knitted garments are worn more often. For example the t-shirt you wear is knitted, mostly it’s cotton single jersey.
Jersey can be made in various types of fabrics: cotton, polyester, nylon, rayon, etc. Spandex can be added to any of these to add stretch.
The early version of the fabric was used for fishermen’s clothing and was a heavier weight fabric than it is today. The Jersey term refers to the knitted product without a distinct rib.
Originally a jersey knit single yarn knit made by looping hand made wool yarns together. Presently they can be made of different contents such as polyester, cotton, rayon, silk, wool and blends. It’s the simplest knit technique and it could be single or double knit. Most of the T-shirt produced nowadays are with this method.
It’s origin is in the small Jersey Island, U.K., also known for the famous milk cow breed with the same name.
Finally, you should understand that jersey is a knitting technique , thereby any fibres could be used to knit ,we could use natural fibres like cotton or synthetic fibres like polyester.