Coby is a distinctive girls' name in United States, ranking #14207 in 1997 with 5 recorded births. The name reached its all-time peak in 2000 with 10 births ranking #9314. In 1997, approximately 1 in every 348,132 girls born was named Coby. STABLE Recent data shows the name is currently stable.
Coby is a compact English short form of Jacob. That gives it a much clearer source line than the earlier broad discussion of several overlapping variant families.
As a nickname-style form, Coby works because it sounds casual and familiar while still resting on a major biblical classic. Its modern use is more flexible, but the Jacob connection is the clearest core route.