digit that is appended to a number so that an accountant can assure the number's correctness following a computation. As the number is utilized in processing, the identical calculation is performed to see if the new check digit is the same as the original one. If so, the number has been read or written accurately. A variation between the check digits indicates an error possibly due to an omission or transposition.

numeric coding facilitating check clearing among banks. The ABA numbering system, managed by the American Bankers Association, assigns a unique identifier to each U.S. financial institution. The ABA number is printed as the numerator (upper portion) of a fraction appearing in the upper right corner on checks; the denominator is the bank's check routing symbol, which identifies the Federal Reserve Bank servicing that financial institution.