A block vote is a large number of votes that are all cast in the same way by one person on behalf of a group of people.
block vote in British English
noun
British
(at a conference, esp of trade unionists) the system whereby each delegate's vote has a value in proportion to the number of people he or she represents
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Examples of 'block vote' in a sentence
block vote
But he will not commit to ending unions' block vote in Labour conferences and leadership elections.