A CSV file, or Comma-Separated Values file, is a simple text format used to store tabular data, such as spreadsheets or databases. Each line in a CSV file represents a row of data, and the values in that row are separated by commas. This format makes it easy to import and export data between different software applications, like Microsoft Excel or Google Sheets. CSV files are widely used because they are easy to read and write for both humans and machines. They can be opened with any text editor and are compatible with many programming languages, making them a popular choice for data exchange and storage.