square metre vs Australian spelling

square metre and Australian spelling both are nouns.

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

square metre (noun)	Australian spelling (noun)
a unit of measurement for area, defined as the area of a square with sides of exactly 1 metre; a centiare is 1/100th of an are	English orthography used in Australia (characterized by 'analyse', 'centre', 'usable')