I'll be heard in church! (5)
I believe the answer is:
'church' is the definition.
The answer and definition can be both man-made objects as well as being singular nouns.
Perhaps they are linked in a way I don't understand?
'i'll be heard' is the wordplay.
'be heard' shows a homophone (sound like).
'ill' sounds like 'AISLE'.
'in' acts as a link.
Can you help me to learn more?
(Other definitions for aisle that I've seen before include "The way to get married in church?", "Path between seats in church", "Passageway between blocks of seats", "Supermarket feature", "Here comes the bride".)