Recurrent stress? (6)
I believe the answer is:
rhythm
'stress?' is the definition.
(thesaurus)
I can't explain the remainder of the clue.
Can you help me to learn more?
(Other definitions for rhythm that I've seen before include "Regular beat in music" , "Pulse, beat" , "A musical essential" , "The basic beat, of a piece of music say" , "Poetic pattern" .)