Lines of different widths and sizes representing data, that when read determine what the scanned object is. Barcodes are often used to help organize and index information or prices about an object. A Barcode is an optical, machine-readable, representation of data; the data usually describes something about the object that carries the barcode.

The lines (bars) and spaces that is affixed to retail store items, identification cards, and postal mail to identify a particular product number, person, or location. The code uses a sequence of vertical bars and spaces to represent numbers and other symbols. A bar code symbol typically consists of five parts: a quiet zone, a start character, data characters (including an optional check character), a stop character, and another quiet zone.