scenario, user story, use case
Here is a link to the most straightforward explanation around these concepts I have seen.
In case you don’t want to drill down to the link above, following is a excerpt.
I’ve tried answering this question so many times and in so many ways: “What’s the difference between a use case and a user story?”
I know what each is, I know how to describe each; I’ve described each and even how to relate the two. I’ve finally concluded that a user story is to a use case as a gazelle is to a gazebo.
See if you can describe the difference without just enumerating what each is.
As the Mad Hatter asked: “Why is a raven like a writing desk?”
A better answer is A user story is the title of one scenario whereas a use case is the contents of multiple scenarios .