Key passage in recital (4)
I believe the answer is:
isle
'key' is the definition.
(key can mean a small island)
'passage in recital' is the wordplay.
'passage' becomes 'aisle' (aisle can mean a path or passageway).
'in recital' shows a homophone (sound like).
'aisle' is a homophone of 'ISLE'.
(Other definitions for isle that I've seen before include "Dogs, say" , "Eg, Iona" , "man with capital?" , "Such as Man or Bute" , "cut-off location" .)