Concert souvenir (4)
I believe the answer is:
stub
'concert souvenir' is the definition.
(I've seen this in another clue)
This is all the clue.
(Other definitions for stub that I've seen before include "Strike against hard object - one's toe, perhaps" , "Broken-off end" , "Knock (toe); short remnant" , "Tooth remnant" , "Truncated remnant" .)