At front of Berkeley Square picked up land (5)
I believe the answer is:
benin
'land' is the definition.
(I know that Benin is an African nation)
'at front of berkeley square picked up' is the wordplay.
'at front of' indicates taking the first letters.
'square' becomes 'nine' (nine is a square number).
'picked up' shows that the letters should be reversed in order.
The initial letter of 'berkeley' is 'b'.
'nine' backwards is 'enin'.
'b'+'enin'='BENIN'
(Other definitions for benin that I've seen before include "French-speaking West African country" , "Nation" , "West Africa country, formerly a French colony" , "part of Africa" , "Country W. of Nigeria" .)