a common animal with four legs, fur, and a tail. Dogs are kept as pets or trained to guard places, find drugs etc → puppy.——朗文当代大辞典

A domesticated carnivorous mammal, Canis familiaris (or C. lupus familiaris), which typically has a long snout, an acute sense of smell, non-retractile claws, and a barking, howling, or whining voice, widely kept as a pet or for hunting, herding livestock, guarding, or other utilitarian purposes.——牛津当代大辞典  @en