Part of beach? Definitely sounds like it (9)
I believe the answer is:
foreshore
'part' is the definition.
The definition and answer can be both natural objects as well as being singular nouns.
Perhaps they are linked in a way I don't understand?
'beach? definitely sounds like it' is the wordplay.
'beach?' becomes 'fore' (I can't explain this - if you can you should believe this answer much more).
'definitely' becomes 'sure' (both can mean 'yes').
'sounds like it' shows a homophone (sound like).
'sure' is a homophone of 'shore'.
'fore'+'shore'='FORESHORE'
'of' acts as a link.
(Another definition for foreshore that I've seen is " Area between high and low water marks".)