Sighthounds are a type of hound dog that hunts primarily by sight and speed, unlike scent hounds, which rely on scent and endurance.

Dog types are broad categories of domestic dogs based on form, function, or style of work, lineage, or appearance. Some may be locally adapted dog types that may have the visual characteristics of a modern purebred dog. In contrast, modern dog breeds strictly adhere to long-established breed standards,[note 1] that began with documented foundation breeding stock sharing a common set of inheritable characteristics, developed by long-established, reputable kennel clubs that recognize the dog as a purebred.