Related Clues:

• Dog
• Breed of dog
• A toy it isn't
• Scooby-Doo, for one
• Boar hunter, once
• Powerful canine
• Popular pet … or an apt description for 17-, 28- or 45-Across
• Large dog
• Dogdom's "gentle giant"
• Canute II?
• Big dog
• Large dog breed
• Dog breed
• Pennsylvania's state dog
• The return of 27 across for Hamlet?