ETYM Late Lat. amortisatio, admortizatio. Related to Amortize, Admortization.
(Alternate spelling: amortisation).
1. Payment of an obligation in a series of installments or transfers; SYN. amortisation.
2. The reduction of the value of an asset by prorating its cost over a period of years; SYN. amortisation.

In finance, the ending of a debt by paying it off gradually, over a period of time. The term is used to describe either the paying-off of a cash debt or the accounting procedure by which the value of an asset is progressively reduced (“depreciated”) over a number of years.
The allocation of the cost of an intangible asset - patent rights, copyrights, trademarks, franchises, loan origination fees, and goodwill - over the period during which benefits are derived from that asset.