Definition
A barcode is a machine-readable pattern of bars or squares that encodes an item's identifier so it can be scanned instead of typed.
Barcode meaning and common formats
Common product formats are EAN-13 (13 digits, used on most retail goods outside North America), UPC (12 digits) and Code 128, which can encode letters and numbers for internal labels. Manufacturers assign standard barcodes from a GS1 number range, and businesses can print their own internal codes for items that arrive without one.
Example: a distributor prints 50 × 25 mm labels with internal EAN-13 codes for loose fittings so stores can identify them quickly at stock counts.
A barcode identifies the item; the price and stock level come from the system, not the label. It usually points to a SKU in the item master.