Pop-chart toppers (4)
I believe the answer is:
hits
'pop-chart toppers' is the definition.
(I've seen this in another clue)
This is all the clue.
(Other definitions for hits that I've seen before include "welcome in the theatre world?" , "that please the public?" , "In the 60s these were 'groovy'" , "Raps - successful recordings" , "Top pops" .)