Zack is a name that sounds like its energy: the hard Z, the short vowel, the sharp stop. It's for dogs who are enthusiastic about everything, who have already knocked something over this morning, and who show no signs of slowing down.
The Z Advantage
Z names carry across distance better than almost any other letter; the sound is distinctive, slightly unusual, and cuts through ambient noise. Zack benefits from this while staying completely familiar as a human name. It doesn't require explanation and doesn't sound like a trend; it just sounds like a dog being called home for dinner. Compare it to Zola or Zuzu; all benefit from the same sonic advantage, but with very different personality reads.
The Human Name Route
Zack is a casual spelling of Zach, short for Zachary, which comes from Hebrew Zechariah, meaning "God has remembered." The spelling with a K is the more casual, pet-friendly version. The human name Zack works in both registers without any awkwardness. The crossover is smooth: naming a dog Zack doesn't feel like you named it after a specific person.
A Note on Fit
Zack skews strongly male and medium-to-large in the imagination; it's hard to picture a very small female cat named Zack without the irony being the entire point. For the energetic, friendly, not-particularly-subtle male dog, it's a strong fit. Labs and border collies wear it well. Browse all pet names for more Z-name options.