\Vouch"er\, n.
1. One who vouches, or gives witness or full attestation, to
   anything.
         Will his vouchers vouch him no more?  --Shak.
         The great writers of that age stand up together as
         vouchers for one another's reputation. --Spectator.
2. 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.
3. (Law)
   (a) 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.
   (b) 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. --Blackstone.