African country also occupying centre of huge area (6)
I believe the answer is:
uganda
'african country' is the definition.
(country in Africa)
'also occupying centre of huge area' is the wordplay.
'also' becomes 'and' (both can mean in addition).
'occupying' means one lot of letters goes inside another (inserted letters occupy or enter the word).
'centre of' means to look at the middle letters.
'area' becomes 'a' (maths abbreviation).
The centre of 'huge' is 'ug'.
'ug'+'a'='uga'
'and' placed inside 'uga' is 'UGANDA'.
(Other definitions for uganda that I've seen before include "Country W. of Kenya" , "Idi Amin's native land" , "Landlocked African state" , "East African republic" , "literally the centre for sugar?" .)