veto

Concise Oxford English Dictionary © 2008 Oxford University Press:
veto /ˈviːtəʊ/

▶noun (pl. vetoes) a constitutional right to reject a decision or proposal made by a law-making body.

■ a ban.

▶verb (vetoes, vetoing, vetoed) exercise a veto against.

■ refuse to accept or allow.

– derivatives
vetoer noun.

– origin C17: from L., lit. ‘I forbid’, used by Roman tribunes when opposing measures of the Senate.