Epic are larger stories. In the Storymap Tree you can have as many levels of epics as you like to describe the project. Once you reach a level which cannot be broken down into smaller parts, you create stories. 

Epics can be planned to releases, but cannot be put in sprint – only stories can go into sprints. 

The state of the epic will always follow the state of the stories/epics below it.

Below is an illustration of an ordinary Story, highlighting common icons displayed on cards and what they represent: