Announcer of visitors — return of family ’avoc (8)
I believe the answer is:
doorbell
'announcer of visitors' is the definition.
Although both the answer and definition are singular nouns, I cannot see how they can define each other.
'return of family 'avoc' is the wordplay.
'return of' shows that the letters should be reversed in order.
'family' becomes 'brood' (I've seen this before).
''avoc' becomes ''ell' ('hell' - I've seen this in another clue - said with the 'H' dropped, a cockney accent, like 'havoc' was).
'brood' back-to-front is 'doorb'.
'doorb'+'ell'='DOORBELL'
Can you help me to learn more?
(Other definitions for doorbell that I've seen before include "Push button to ring" , "Bordello with signal fitted to entrance" , "Entrance ringer" , "Ring it to announce presence of arrival in bordello" , "What one rings to be let in" .)