How much is a crore?

Could you please clarify the term "crore" for me? Is it a unit of currency used in a specific country or region? If so, could you provide the country or region where it's commonly used? Also, could you give me an approximate conversion to a more widely recognized currency, such as the US dollar or the euro? Additionally, how does the value of a crore compare to other currency units within the same region or country?