Denny is a diminutive of Dennis or Denison — a name with roots in Dionysius, the Greek god of wine and revelry — that functions independently as a warm, unpretentious male pet name. It's friendly, slightly retro, and carries no significant pop-culture baggage beyond its association with the American diner chain of the same name, which owners either find amusing or choose to ignore entirely.
The Warm, Retro Register
Denny occupies the same vintage-human-name territory as Jerry, Larry, and Barry — names that were solidly mid-century American and have been largely displaced from human naming. On a dog, these names generate a specific warmth: the pet feels like a person, a slightly old-fashioned but deeply good-natured person. Beagles and Labradors suit Denny with natural ease.
Grey's Anatomy and the Sentimental Reading
Denny Duquette, the charming and ill-fated patient in Grey's Anatomy played by Jeffrey Dean Morgan, gave the name an unexpected emotional resonance for viewers of that era. A dog named Denny in a household that watched that storyline may be a quiet tribute — the kind of naming choice that references grief without requiring the owner to explain it in detail. The human name Denny is rare enough that the reference lands clearly for anyone who knows it.
The Counter-Reading: The Diner
Denny's, the American diner chain, is a significant cultural presence. Owners who love the association lean into it cheerfully; those who don't should know it will surface at least occasionally in every introduction of the dog's name.