Large area with national borders, essentially (4)
I believe the answer is:
land
'large area with national borders essentially' is the definition.
I can't judge whether this defines the answer.
'large area with national borders essentially' is the wordplay.
'large' becomes 'L' (eg in clothes sizes).
'area' becomes 'a' (maths abbreviation).
'with' is a charade indicator (letters next to each other).
'national' becomes 'n' (abbreviation listed in Chambers).
'essentially' says to take the centre.
The middle of 'borders' is 'd'.
'l'+'a'+'n'+'d'='LAND'
Can you help me to learn more?
(Other definitions for land that I've seen before include "Gain" , "See 3" , "Come down; territory" , "Alight; country" , "Country, state" .)