The term 'Border Dog' refers to a type of COLLIE, which is a breed of herding dog. The Border COLLIE is a medium-sized dog that is known for its intelligence and agility. It is often used as a working dog on farms and ranches, and is also popular as a family pet. The Border COLLIE is an active and energetic breed that requires plenty of exercise and mental stimulation. They are loyal and devoted to their owners and make excellent companions.