Read aloud key passage (5)
I believe the answer is:
aisle
'passage' is the definition.
(aisle is a kind of passage)
'read aloud key' is the wordplay.
'read aloud' indicates a 'sounds like' (homophone) clue.
'key' becomes 'isle' (I've seen this before).
'isle' is a homophone of 'AISLE'.
(Other definitions for aisle that I've seen before include "A key" , "Passages between seating areas" , "Passage between shelves in supermarket" , "Here comes the bride" , "part of theatre?" .)