What is a breed standard?
Dogs differ in appearance, temperament, mentality and performance.
A breed standard describes what the ideal dog looks like. It also describes which overall appearance and temperament are required. The breed standard also define faults. Some faults influence the assessment of the dogs, others are directly disqualifying. A fault can be the wrong color, wrong bite, aggressiveness, size or proportions of the body.
At exhibitions the dogs are judged accordingly to the breed standard. Some breeds needs to achieve a specific evaluation before being used for breeding.
FCI Federation Cynologique International sets the breed standards
FCI breed standard: Border Terrier