Fish, by the sound of it, in position (5)
I believe the answer is:
place
'position' is the definition.
(I know that place is a type of position)
'fish by the sound of it' is the wordplay.
'fish' becomes 'plaice' (plaice is a kind of fish).
'by the sound of it' shows a homophone (sound like).
'plaice' sounds like 'PLACE'.
'in' is the link.
(Other definitions for place that I've seen before include "Locality" , "Venue" , "Site" , "Endearingly pretty" , "Situation" .)