Divided around one side (5)
I believe the answer is:
cleft
'divided' is the definition.
(similar in meaning)
'around one side' is the wordplay.
'around' becomes 'c' (abbreviation for 'circa').
'one side' becomes 'left' (I've seen this before).
'c'+'left'='CLEFT'
(Other definitions for cleft that I've seen before include "Split (as a stick)" , "split along natural lines" , "Split in the palate" , "Split into two" , "Partially divided" .)