Land is usable, cultivated around river (7)
I believe the answer is:
belarus
'land' is the definition.
The answer and definition can be both locations as well as being singular nouns.
Perhaps there's a link between them I don't understand?
'usable cultivated around river' is the wordplay.
'cultivated' is an anagram indicator.
'around' means one lot of letters goes inside another.
'river' becomes 'r' (abbreviation for river).
'usable' is an anagram of 'belaus'.
'belaus' enclosing 'r' is 'BELARUS'.
'is' is the link.
Can you help me to learn more?
(Other definitions for belarus that I've seen before include "European nation)" , "Minsk's country" , "European republic" , "State" , "East European country, capital Minsk" .)