A custom solution running on the Splunk platform that packages specific files and settings to address specific use cases. An app can contain one or more views and can include knowledge objects such as reports, lookups, scripted inputs, and modular inputs. An app sometimes depends on one or more add-ons for specific functionality.
An example of an app is the Splunk Enterprise Search app.
For more information
On the Splunk Developer Portal:
On the Splunk UI Portal: