diagonalisation vs Australian spelling

diagonalisation and Australian spelling both are nouns.

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

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