Mark - of distinction? (4)
I believe the answer is:
note
This clue is a double definition.
'mark' is the first definition.
(mark can mean to note or remember)
'distinction?' is the second definition.
(I know that distinction can be written as note)
'of' is the link.
(Other definitions for note that I've seen before include "Make a mental or written reminder" , "Observation" , "Characteristic" , "A piece of paper money" , "Tone of a short record" .)