The Collaborative International Dictionary of English v.0.48:

Amortization \A*mor`ti*za"tion\, n. [LL. amortisatio,
   admortizatio. See Amortize, and cf. Admortization.]
   1. (Law) The act or right of alienating lands to a
      corporation, which was considered formerly as transferring
      them to dead hands, or in mortmain.
      [1913 Webster]

   2. The extinction of a debt, usually by means of a sinking
      fund; also, the money thus paid. --Simmonds.
      [1913 Webster]

WordNet (r) 3.0 (2006):

amortization
    n 1: the reduction of the value of an asset by prorating its
         cost over a period of years [syn: amortization,
         amortisation]
    2: payment of an obligation in a series of installments or
       transfers [syn: amortization, amortisation]

Moby Thesaurus II by Grady Ward, 1.0:

77 Moby Thesaurus words for "amortization":
   abalienation, acquitment, acquittal, acquittance, alienation,
   amortizement, assignation, assignment, bargain and sale, barter,
   bequeathal, binder, cash, cash payment, cession, clearance,
   conferment, conferral, consignation, consignment, conveyance,
   conveyancing, debt service, deeding, defrayal, defrayment,
   deliverance, delivery, demise, deposit, disbursal, discharge,
   disposal, disposition, doling out, down payment, earnest,
   earnest money, enfeoffment, exchange, giving, hire purchase,
   hire purchase plan, installment, installment plan,
   interest payment, lease and release, liquidation, monthly payments,
   never-never, paying, paying off, paying out, paying up, payment,
   payment in kind, payoff, prepayment, quarterly payments, quittance,
   regular payments, remittance, retirement, sale, satisfaction,
   settlement, settling, sinking-fund payment, spot cash, surrender,
   trading, transfer, transference, transmission, transmittal,
   vesting, weekly payments



Bouvier's Law Dictionary, Revised 6th Ed (1856):

AMORTIZATION, contracts, English law. An alienation of lands or tenements in
mortmain. 2 Stat. Ed. I.
     2. The reduction of the property of lands or tenements to mortmain.