A comma-separated values (CSV) file is "a delimited text file that uses a comma to separate values" according to Wikipedia. It stores tabular data (numbers and text) in plain text. Blender itself does not have importers or exporters for CSV files, but the format is used by any number of add-ons for importing and exporting data to other programs. Use this tag for Blender-specific questions about the use of CSV Files.
Wikipedia describes the Comma-separated values (CSV) file format as
a delimited text file that uses a comma to separate values. Each line of the file is a data record. Each record consists of one or more fields, separated by commas.
None of Blender's build-in importers or exporters process CSV files, but there are any number of third-party add-ons that do, usually as a way of exchanging data with other programs that export CSV, a common practice ins scientific programs, for example.
This format is also easy to parse in Python, so there are many third-party Blender Python scripts that use it.
Use this tag for Blender-specific questions about the use of CSV Files.
