decolonization vs decolonisation

decolonization and decolonisation both are nouns.

Word	Noun	Adjective	Verb	Adverb
decolonization	Yes	No	No	No
decolonisation	Yes	No	No	No

As nouns, decolonization and decolonisation are synonyms defined as:

decolonization and decolonisation: the action of changing from colonial to independent status

decolonization (noun)	decolonisation (noun)
the action of changing from colonial to independent status	the action of changing from colonial to independent status