Nicky ranks at #568 with 219 entries, registered male. It is a classic short form of Nicholas (or occasionally Dominic), and it lives in the same warm-and-friendly pet-name register as Bobby, Tommy, and Jimmy — names that read as a pet's everyday call-name rather than their formal license-form name.
The Italian-American lineage
Nicky carries a specific cultural fingerprint in the United States: the name shows up disproportionately in Italian-American households, where Nicholas-to-Nicky is a generations-deep tradition. Owners reaching for Nicky on a pet are often quietly nodding to a grandfather or uncle who wore it. The Goodfellas-and-Sopranos register is real but not dominant; for most owners the warmth is the point.
Breed lean and sound
Two syllables, front-stressed (NIK-ee), with a hard K that recalls cleanly across a yard. The name lands on medium-sized friendly breeds — Beagles, Cocker Spaniels, Shih Tzus, and shelter mixes — and on indoor cats with sociable personalities. It works less well on intimidating breeds; the diminutive ending pulls the register toward warmth.
The human crossover
The Nicholas baby name page shows the formal version sitting solidly in the SSA top range, while Nicky as a standalone name is rare on the human chart. Pet Nicky essentially owns the diminutive form on the cultural map. For more in this register, browse the broader pet name index.