From Longman Dictionary of Contemporary Englishcasting voteˈcasting ˌvote noun [countable usually singular] British English PPVDECIDEthe vote of the person in charge of a meeting, which can be used to make a decision when there is an equal number of votes supporting and opposing a proposal
Examples from the Corpus
casting vote• Without hesitation the General threw his casting vote in favour of the gallows.• I had to assert the authority of my casting vote.• There was heated debate, but by the casting vote of the chairman we got our grant.• Verity Lambert would have artistic control over, and generally the casting vote in any decisions about, the programme.• The Chair has the casting vote in the case of a tie.• The only solution seems to be to rotate the casting vote, but there are always Trollopean difficulties and rivalries.From Longman Business Dictionarycasting voteˈcasting ˌvote [countable] an extra vote that someone in charge of a meeting can have, which is only used if there are exactly the same number of votes for and against somethingHe missed being sacked only by the Chairman’s casting vote. → vote 