decentralisation vs British spelling

decentralisation and British spelling both are nouns.

Word	Noun	Adjective	Verb	Adverb
decentralisation	Yes	No	No	No
British spelling	Yes	No	No	No

decentralisation (noun)	British spelling (noun)
the spread of power away from the center to local branches or governments	English orthography used in the UK, Ireland and most of the Commonwealth (characterized by 'analyse', 'centre' and 'useable')