A dataset is a collection of data that you define and maintain for a specific business purpose. It is represented as a table, with fields for columns and field values for cells. You can view and manage datasets with the Datasets listing page. You can use datasets as the basis for visualization-rich Pivot reports and extend datasets in Search.
The Splunk Datasets Add-on, available from Splunkbase, gives Splunk Enterprise users additional dataset management capabilities. Splunk Cloud users have the Splunk Datasets Add-on by default.
For more information
In the Knowledge Manager Manual