One of the British Isles (6)
I believe the answer is:
thanet
'british isles' is the definition.
Both the definition and answer are singular nouns.
Maybe they are linked in a way I don't understand?
'one of the' is the wordplay.
I cannot quite understand how this works, but
'one' could be 'ane' (synonyms) and 'ane' is found within the answer.
'the' could be 't' (the is pronounced as a 't' sound in some dialects) and 't' is located in the answer.
This may be the basis of the clue (or it may be nonsense).
Can you help me to learn more?
(Other definitions for thanet that I've seen before include "Kent island, scene of many Norse invasions" , "District of Kent" , "Area of Kent, an island in name only" , "Isle in Kent" , "Northeast part of Kent" .)