By which one is known (4)
![Ross](/clue/static/ross-mug.min.png)
I believe the answer is:
name
'by which one is known' is the definition.
(I've seen this before)
This is all the clue.
(Other definitions for name that I've seen before include "celebrity" , "Handle" , "By which a person is known" , "Designation; fame" , "Famous person; reputation" .)