Dog

Etymology and related terminology
Dog is the common use term that refers to members of the subspecies Canis lupus familiaris. The term can also be used to refer to a wider range of related species, such as the members of the genus Canis, or "true dogs", including the wolf, coyote, and jackals; or it can refer to the members of the subfamily Caninae, which would also include the African wild dog; or it can be used to refer to any member of the family Canidae, which would also include the foxes, bush dog, raccoon dog, and others. Some members of the family have "dog" in their common names, such as the raccoon dog and the African wild dog. A few animals have "dog" in their common names but are not canids, such as the prairie dog.
The English word dog comes from Middle English dogge, from Old English docga, a "powerful dog breed". The term may derive from Proto-Germanic dukkōn, represented in Old English finger-docce ("finger-muscle"). The word also shows the familiar petname diminutive -ga also seen in frogga "frog", picga "pig", stagga "stag", wicga "beetle, worm", among others. Due to the archaic structure of the word, the term dog may ultimately derive from the earliest layer of Proto-Indo-European vocabulary, reflecting the role of the dog as the earliest domesticated animal.