‘Comma-separated values’ is a standard format for spreadsheet data. Data is represented in a plain text file, with each data row on a new line and commas separating the values on each row. As a very simple open format it is easy to consume and is widely used for publishing open data. Source: ODH

It is often used to exchange data between differently similar applications. The CSV file format is useable by KSpread, OpenOffice Calc and Microsoft Excel spreadsheet applications. Many other applications support CSV to import or export data. Source: http://edoceo.com/utilitas/csv-file-format, cited by EU OD

It is a computer data file used for implementing the tried and true organizational tool, the Comma Separated List. The CSV file is used for the digital storage of data structured in a table of lists form. Each line in the CSV file corresponds to a row in the table. Within a line, fields are separated by commas, and each field belongs to one table column. CSV files are often used for moving tabular data between two different computer programs (like moving between a database program and a spreadsheet program).

Source: US OD