A little dictionary of words used in the Auto-id and POS industry

Check number
A sign most often situated directly before the last sign. The check number is there to check that the barcode scanner has read the correct information.

Density
Number of signs per measure. The density gives a measure on the codes compactness.

Discrete code
A barcode where every sign has been separeated with a white space that doesn’t carry information.

Code element
Common description of bars or spaces. 

Code relation
The width between the thick and the thin code elements.

Continuous code
A barcode where you also can find information in the white code elements.

Margin
The empty spaces directly before and after the stop signs. 

Space
A light code element.

Module
The width of the thinnest code element. Other code elements are built of multiples. They are indicated in mm or mils (1/1000 tum).

Start- and Stop signs
The first and last sign in a barcode.

Bar
A dark code element. 

Barcode
A row of diverse sized black lines with white spaces in between according to a specified system.

Sign
A code element, which in conjunction with other signs, can be read as a number, a letter or a symbol.

Sign space
The space between the last code element in a sign, and the following signs first code element.