Australian spelling vs diagonalisation

Australian spelling and diagonalisation both are nouns.

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

Australian spelling (noun)	diagonalisation (noun)
English orthography used in Australia (characterized by 'analyse', 'centre', 'usable')	changing a square matrix to diagonal form (with all non-zero elements on the principal diagonal)