Definition of voucher

• n. - One who vouches, or gives witness or full attestation, to anything.
• n. - A book, paper, or document which serves to vouch the truth of accounts, or to confirm and establish facts of any kind; also, any acquittance or receipt showing the payment of a debt; as, the merchant's books are his vouchers for the correctness of his accounts; notes, bonds, receipts, and other writings, are used as vouchers in proving facts.
• n. - The act of calling in a person to make good his warranty of title in the old form of action for the recovery of lands.
• n. - The tenant in a writ of right; one who calls in another to establish his warranty of title. In common recoveries, there may be a single voucher or double vouchers.