noun

1. a person who vouches, as for the truth of a statement
2. a paper serving as evidence or proof; specif., a receipt or statement attesting to the expenditure or receipt of money, the accuracy of an account, etc.
3. ☆ a document granting a family a certain sum per child, from public education funds, for use as partial tuition to a private or parochial school, thereby making possible enrollment there instead of in the local public school

Etymology: substantive use of Anglo-Fr voucher, to vouch