In barcoding, the X Dimension is the nominal (intended or specified) width of the narrow bar in a Barcode. Every barcode has an X dimension. The widths of wider bars and spaces are specified as a multiple of the X Dimension.

The X Dimension is used to determine a barcode’s Density. The smaller the X Dimension, the higher the density.

The actual achieved width of the narrow bar is known as the Y Dimension.

XML is a flexible way to create common information formats and share both the format and the data on the World Wide Web, Intranets, and elsewhere. For example, computer makers might agree on a standard or common way to describe the information about a computer product (processor speed, memory size, and so forth) and then describe the product information format with XML. Such a standard way of describing data would enable a user to send an intelligent agent (a program) to each computer maker's Web site, gather data, and then make a valid comparison. XML can be used by any individual or group of individuals or companies that wants to share information in a consistent way.