isomerisation vs British spelling

isomerisation and British spelling both are nouns.

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

isomerisation (noun)	British spelling (noun)
the conversion of a compound into an isomer of itself	English orthography used in the UK, Ireland and most of the Commonwealth (characterized by 'analyse', 'centre' and 'useable')