The Collaborative International Dictionary of English v.0.48:

Jersey \Jer"sey\, n.; pl. Jerseys. [From Jersey, the largest
   of the Channel Islands.]
   [1913 Webster]
   1. The finest of wool separated from the rest; combed wool;
      also, fine yarn of wool.
      [1913 Webster]

   2. A kind of knitted jacket; hence, in general, a
      closefitting jacket or upper garment made of an elastic
      fabric (as stockinet).
      [1913 Webster]

   3. One of a breed of cattle in the Island of Jersey. Jerseys
      are noted for the richness of their milk.
      [1913 Webster]