Coby is a distinctive boys' name in England & Wales, ranking #898 in 1996 with 16 recorded births. The name reached its all-time peak in 2019 with 213 births ranking #236. In 1996, approximately 1 in every 19,907 boys 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.