When I am reading a promotion dossier or a scholarly paper or a student's paper, I am first asking if the work is good. Does it meet sensible expectations? Is it well written and supported? Is it fishy--plagiarized, unedited, ...
As I am reading, I may discover there is lots more there than I would have expected. The contribution to scholarship is significant. The student paper could have been written by a distinguished colleague. (It has no gaping holes or problems, although that is also demanded for good work.) Perhaps the work violates all the conventional rules, but stands on its own, and is manifestly outstanding--rare but possible. I discover that the work or the paper is excellent, and I want to share it with colleagues.
Excellent student work in my university context is impeccable scholarship and exhibits consistent critical thinking. Excellent faculty work makes a strong contribution to the scholarly enterprise.
In the world of Harry Potter, there are passing grades: Acceptable, Exceeds Expectations, and Outstanding. For me, excellent work really is outstanding. Sometimes excellent work just exceeds my expectations, and I am grateful for it.