Selenese is the set of Selenium commands which are used to test your web application. The tester can test the broken links, the existence of some object on the UI, Ajax functionality, alerts, window, list options, and a lot more using Selenese.
Action: Commands which interact directly with the application
Accessors: Allow the user to store certain values to a user-defined variable
Assertions: Verifies the current state of the application with an expected state
