What is the meaning of Cocker spaniel?

One of a breed of small or medium-sized spaniels kept for hunting or retrieving game or for household pets. They usually weigh from eighteen to twenty-eight pounds. They have the head of fair length, with square muzzle, the ears long and set low, the legs short or of medium length, and the coat fine and silky, wavy but not curly. Various colors are bred, as black, liver, red, black and white, black and tan, etc.