Channel island area and state (4)
I believe the answer is:
iowa
'state' is the definition.
(Iowa is an example)
'channel island area' is the wordplay.
'channel island' becomes 'iow' (Isle of Wight).
'area' becomes 'a' (maths abbreviation).
'iow'+'a'='IOWA'
'and' acts as a link.
(Other definitions for iowa that I've seen before include "part of United States" , "State of USA" , "Midwest US state" , "'Hawkeye State'" , "part of US" .)