fossilisation vs Australian spelling

fossilisation and Australian spelling both are nouns.

Word	Noun	Adjective	Verb	Adverb
fossilisation	Yes	No	No	No
Australian spelling	Yes	No	No	No

fossilisation (noun)	Australian spelling (noun)
becoming inflexible or out of date	English orthography used in Australia (characterized by 'analyse', 'centre', 'usable')
the process of fossilizing a plant or animal that existed in some earlier age; the process of being turned to stone