tumour vs Australian spelling

tumour and Australian spelling both are nouns.

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

tumour (noun)	Australian spelling (noun)
an abnormal new mass of tissue that serves no purpose	English orthography used in Australia (characterized by 'analyse', 'centre', 'usable')