Hundi is a term used in Indian banking that refers to an instrument similar to a check. However, there are several synonyms for the term used across different regions and languages in India. In some regions, it is called a "shah-jog" or a "shah-jogi" while in others, it is referred to as a "dabba" or a "dabbi". Another synonym commonly used is "havala" which is of Arabic origin and is used widely in Middle Eastern countries too. It is essential to note that while the term may differ, the concept remains the same - an instrument used for transferring funds between parties.