User Story
A user story is a description of a feature as seen from the perspective of the user. It consist of three parts, and is always phrased like this:
As
<user>I want to<action>so that I<reason>
Specifying the user is important so we know who is going to do the action, then we describe the action so we know what they would like to do, and then finally we ask why, so that we can understand the intent of the user.
One example of this is
As a student I want to have constant feedback so that I use the feedback to improve.
Here we learn that the student want to have a feature that can give them constant feedback, we can use the reason to see if we can deliver something that is close to their goal but still captures their intent.