Bishop to apportion vote (6)
I believe the answer is:
ballot
'vote' is the definition.
(balloting is a kind of voting)
'bishop to apportion' is the wordplay.
'bishop' becomes 'B' (chess abbreviation).
'to apportion' becomes 'allot' (I've seen this before).
'b'+'allot'='BALLOT'
(Other definitions for ballot that I've seen before include "Voting procedure" , "Voting paper" , "Lottery (eg, for tickets)" , "Document listing the alternatives to vote for" , "The process of voting" .)