Halves, dry in pieces (7)
I believe the answer is:
bisects
'halves' is the definition.
(I've seen this in another clue)
'dry in pieces' is the wordplay.
'dry' becomes 'sec' (similar in meaning).
'in' is an insertion indicator.
'pieces' becomes 'bits' (bit is a kind of piece).
'sec' inserted into 'bits' is 'BISECTS'.
(Other definitions for bisects that I've seen before include "Cuts in half" , "Cuts in two" , "Divides into two parts" , "Divides in equal halves" .)