.ARFF File Extension
File TypeAttribute-Relation File Format
What is an ARFF file?
File used by Weka, a machine learning application; saved in the the Attribute Relation File Format (ARFF) and contains a header section with a list of types (numeric, nominal string, date) and a data section with the values.
Weka and ARFF files can be used for tasks such as data clustering and regression.