A standard CSV file is a simple table of data, each line represents a row of data, and each row is split by a comma. It is stored as plain text and therefore contains absolutely no formatting.
However, CSV files are very popular as they are almost entirely supported by almost every system - they are also extremely simple to work with.
Since CSV files have no formatting, if they were to be used as the data for a website, then the description of the CSV file would have to be stored in another file.
XML is a very popular file format, it is also plain text, but is highly structured and allows complex data structures to be stored.
Therefore, using the existing CSV standard and the existing XML standard a method was found to store important information about what the CSV file meant, in XML format.
The file format to contain information in XML format about the CSV file is named XCSV.