Koby

Koby can be a short form of Jacob, reaching the older name through its final sounds rather than its opening. Jacob is traditionally linked with the Hebrew word for a heel and the biblical account of a child born holding his twin brother's heel. That gives Koby a connection with a much older name despite its informal shape.

Coby is a close spelling comparison, and either can stand as a complete first name. Families may choose Koby to honor a Jacob while using a different everyday sound. Similar spellings can have separate histories in other languages, so the Jacob explanation is most helpful when that is the family's intended connection rather than a meaning assigned to every lookalike.