(Source: https://en.wikipedia.org/wiki/Barcode)

A barcode (also bar code) is a visual, machine-readable representation of data; the data usually describes something about the object that carries the barcode. Traditional barcodes systematically represent data by varying the widths and spacings of parallel lines, and may be referred to as linear or one-dimensional (1D). Later, two-dimensional (2D) variants were developed, using rectangles, dots, hexagons and other geometric patterns, called matrix codes or 2D barcodes, although they do not use bars as such. In retail, cashiers scan the barcode to ring up purchases when being paid for.

See also

• barcode
• barcode_tattoo
• qr_code