When one gains independence as a very large area (4)
I believe the answer is:
asia
'large area' is the definition.
(I've seen this before)
'when one gains independence' is the wordplay.
'when' becomes 'as' (eg 'when I walked' means 'as I walked').
'one' becomes 'a' (a thing is one thing).
'gains' means one lot of letters goes inside another.
'independence' becomes 'I'.
'as'+'a'='asa'
'asa' enclosing 'i' is 'ASIA'.
'as a very' is the link.
This may not be correct. Some or all of it may belong to another bit of the clue.
Can you help me to learn more?
(Other definitions for asia that I've seen before include "Large continent" , "It has most of the earth's population" , "lands in the east" , "One-third of all land" , "The nations of the East, collectively" .)