"Polka" follower (3)
I believe the answer is:
dot
'polka follower' is the definition.
(I've seen this in another clue)
This is all the clue.
(Other definitions for dot that I've seen before include "Cotton, say" , "Flyspeck: period in a web address" , "'Spot, tiny mark (3)'" , "One of the signals in Morse code" , "One signal used in Morse code" .)