From Longman Dictionary of Contemporary Englishballot paperˈballot ˌpaper noun [countable] PPVVOTE/ELECTa piece of paper on which you record your votespoiled ballot papers (=ones that have been marked incorrectly and so cannot be counted)
Examples from the Corpus
ballot paper• As in Ireland some voters would find the ballot paper confusing.• Also on the ballot paper was the one candidate, Lucy Courtney, for the post of senior vice-president.• Voters also heavily endorsed a clause on the ballot paper calling for the convening of a constituent assembly to reform the Constitution. 