A trace (4)
'a trace' is the definition.
(I've seen this before)
This is the entire clue.
(Other definitions for mark that I've seen before include "Matthew, . . . ., Luke and John" , "Visible impression" , "Indication - notice" , "What one might have paid old German" , "Target; become stained" .)
'a trace' is the definition.
(I've seen this before)
This is the entire clue.
(Other definitions for dreg that I've seen before include "Small amount left over" , "Small quantity (of residue?)" , "Trace" .)