A dog breed is a group of dogs, represented by a sufficient number of individuals to be interbred without forced inbreeding to stably transfer its specific characteristics over generations. Purebred dogs of same breed have similar characteristics of appearance and behavior, primarily because they come from a select set of ancestors who had the same characteristics . They are accommodated to certain natural and economic conditions and usually exploitation while differ from other breeds by exclusive conformation traits and working abilities.

Aboriginal groups or pariah dogs establish themselves near human population, and further develop and maintain themselves without further selection. Neither they carry any specialized working dog functions. Working, hunting and other functional breeds most likely appeared when there is a demand for certain traits that are prevalent to the extension of the point one can devote his time and efforts to establish and maintain the group of dogs that perfect in certain traits valuable for that individual.

Initially the selections would have centered on domestication and useful behavior such as barking at strange creatures, livestock guarding or hunting ability. Some dog breeds, such as Saluki or New Guinea Singing Dogs , have been bred for specific characteristics for thousands of years. Some working dog breeds such as German Shepherds or Labrador Retriever are established for hundreds years. Later, dogs were also selected for attractive and distinctive forms, resulting in a vast variety of different breeds. Similar dog breeds are classified by dog registries in Dog Breeds Groups.

At a certain point of dog breed development, group of individuals that have dogs of the same breed unite into a National Breed club, describe their dogs in a specific language by writing a breed standard . They describe the most desirable breed specimen and also specify working abilities, as well as undesirable traits for purebred dogs that can belong to this group of dogs. National Breed Clubs promote dog breeds by joining a local []popular]] dog breed registry, as well as internationally, by joining international organizations. Many traditional dog breeds are recognized by the main breed registries are said to be "purebred".