Nod and wait in order to be heard (3)
I believe the answer is:
cue
'nod' is the definition.
(thesaurus)
I don't understand how the rest of the clue works.
Can you help me to learn more?
(Other definitions for cue that I've seen before include "Reminder to do something" , "Prompting" , "Sign" , "Sports implement" , "Billiards stick" .)