Comma separated values

Definition
A  comma separated values (CSV) file 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."

Overview
CSV files are often used for moving tabular data between two different computer programs (like moving between a database program and a spreadsheet program).