Anything made using Twine can be called by any name. They are no rules on naming conventions and everything from experimental games to more traditional novels can be created in Twine. Everything is welcome. In general, the Twine editor calls individual projects Stories.
Stories can be published to HTML and are readable in a web browser without Twine. In their published form, they can also be imported into Twine for further editing.
When created, each Story is each given a series of letters and numbers called an Interactive Fiction IDentifier (IFID).
The IFID always retained. This helps authors track their projects on different platforms, or if other authors have copied or tried to claim it as their own without their knowledge or consent.