amortization vs defrayment

amortization and defrayment both are nouns.

Word	Noun	Adjective	Verb	Adverb
amortization	Yes	No	No	No
defrayment	Yes	No	No	No

As nouns, defrayment is a hypernym of amortization; that is, defrayment is a word with a broader meaning than amortization:

amortization: payment of an obligation in a series of installments or transfers
defrayment: the act of paying money

Other hypernyms of amortization include defrayal, payment.

amortization (noun)	defrayment (noun)
payment of an obligation in a series of installments or transfers	the act of paying money
the reduction of the value of an asset by prorating its cost over a period of years