That of a standing ovation? (3)
I believe the answer is:
din
'ovation?' is the definition.
Although both the answer and definition are singular nouns, I cannot see how one could define the other.
'that of a standing' is the wordplay.
'that of' says the answer is hidden in the clue.
'DIN' is hidden in the letters of 'standing'.
Can you help me to learn more?
(Other definitions for din that I've seen before include "Loud unpleasant noise" , "Distracting noise" , "Hubbub" , "'Loud, harsh noise (3)'" , "Loud noise, racket" .)