Australian spelling vs spelling

Australian spelling and spelling both are nouns.

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

As nouns, spelling is a hypernym of Australian spelling; that is, spelling is a word with a broader meaning than Australian spelling:

Australian spelling: English orthography used in Australia (characterized by 'analyse', 'centre', 'usable')
spelling: forming words with letters according to the principles underlying accepted usage

Australian spelling (noun)	spelling (noun)
English orthography used in Australia (characterized by 'analyse', 'centre', 'usable')	forming words with letters according to the principles underlying accepted usage