Openings in Commonwealth area involving a Commonwealth state (6)
I believe the answer is:
canada
'commonwealth state' is the definition.
(Canada is part of the Commonwealth)
'openings in commonwealth area involving a' is the wordplay.
'openings in' says to take the initial letters (I've seen 'opening in' mean this).
'area' becomes 'ada' (I can't explain this - if you can you should believe this answer much more).
'involving' is an insertion indicator.
'a' becomes 'an'.
The first letter of 'commonwealth' is 'c'.
'c'+'ada'='cada'
'cada' placed around 'an' is 'CANADA'.
(Other definitions for canada that I've seen before include "North American goose" , "Second-largest country in the world by area" , "New World country" , "N American country" , "Country with six time zones" .)