Great idea. I've created a new article that defines some common terms used by CaseComplete:
It's just a start, so if you (or anyone else reading this) thinks of other terms you'd like included in the list, let us know.
Also, I'll take this opportunity to mention a couple features that are easy to miss that you may find helpful: CaseComplete comes with a PowerPoint presentation, Introduction to Use Cases, which is useful to go through with stakeholders who are new to use cases (access this from the Getting Started section of the start page in CaseComplete). Second, on the details forms (e.g. use case details), there is a question mark button in the upper right. Clicking it opens a side-window which shows information about each field in the form as you click on the field.