touchback - (American football) a play in which the opposing team has kicked the football into your end zone.
From Wikipedia, the free encyclopedia. A check digit is a form of redundancy check used for error detection on identification numbers, such as bank account numbers, which are used in an application where they will at least sometimes be input manually. It is analogous to a binary parity bit used to check for errors in computer-generated data.
Check digit calculator. The check digit is calculated from all the other numbers in the barcode and ensures the integrity of your barcode number. A check digit is a calculated one-digit number used to ensure data integrity. The check digit is the last digit of a barcode number.