Traditionally, a jersey is an item of knitted clothing, generally made of wool or cotton, with sleeves, worn as a pullover, as it does not open at the front, unlike a cardigan. It is usually close-fitting and machine knitted in contrast to a guernsey that is more often hand knit with a thicker yarn. The word is usually used interchangeably with sweater.
Alternatively, the shirt worn by members of a sports team as part of the team uniform is also referred to as a jersey.
Jersey, in the Channel Islands, was famous for its knitting trade in medieval times, and because of that original fame, the name "jersey" is still applied to many forms of knitted fabric, which transferred to the garments made from the fabric.
A sports jersey is a shirt worn by a member of a team which identifies their affiliation with the team. A jersey identifies the athlete's name and/or number, generally showing the colors and logo of the team.The jersey's numbers are there so it can be easier to identify the player from their teams members out in the field. Since everyone is wearing the same uniform and it's hard to tell them apart on/in the field.
A jersey may also include the logo of the team's sponsor.
Cycling jerseys of a specific color or pattern represent certain statuses in road cycling, such as the yellow jersey of the leader of the general classification in the Tour de France, or the rainbow jersey for the world champion. Cycling jerseys are usually made of synthetic microfiber material to aid in wicking sweat away from the skin to allow it to evaporate.
The main garment of an ice hockey uniform, which was traditionally called a sweater, is increasingly known as a hockey jersey. Basketball jerseys are usually sleeveless. Baseball jerseys are usually button up.
In Australian rules football, the player's shirt is known as a "guernsey".
Other examples are the third jersey, hockey jersey, basketball uniform, baseball uniform and gridiron football uniform.