from The Century Dictionary and Cyclopedia
- n. A dog that hunts in the night, especially one used by poachers.
Sorry, no etymologies found.
What is more, she did so, which was naughty of her, for on one such occasion she slipped back to the house when her parents were asleep, followed only by her "night-dog," the watchful Ivana, and returned at dawn just as they had discovered that she was missing, singing and laughing and jumping from stone to stone with the agility of her own pet goat.
"night-dog" -- that is what she called it -- to Tabitha, saying that she did not mind sleeping on a height.
a night-dog, on the roofs of the Atreidae, waiting for the signal fires that should announce the fall of sacred Ilion!
Then Sam, he began howling, and so he had what you white people call the nightmare, but this time it was the night-dog. "