oesophagus vs Australian spelling

oesophagus and Australian spelling both are nouns.

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

oesophagus (noun)	Australian spelling (noun)
the passage between the pharynx and the stomach	English orthography used in Australia (characterized by 'analyse', 'centre', 'usable')