to pay off (a mortgage, debt, etc) gradually, usu by periodic instalments or contributions to a sinking fund
to write off the initial cost of (an asset, esp in business) over an agreed period
dated to transfer (land, etc) in mortmain
amortizable adj
amortization /-ʹzaysh(ə)n/ noun
[Middle English amortisen to deaden, alienate in mortmain, modification of early French amortiss-, stem of amortir, ultimately from ad- + Latin mort-, mors death]