Voucher
VOUCHER (from " to vouch," to warrant, answer for, O. Fr. her, to cite, call in aid, Lat. vocare, to call, summon), any document in writing which confirms the truth of accounts or establishes other facts, more particularly a receipt or other evidence in writing which establishes the fact of the payment of money.
Note - this article incorporates content from Encyclopaedia Britannica, Eleventh Edition, (1910-1911)