dead centre vs Australian spelling

dead centre and Australian spelling both are nouns.

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

dead centre (noun)	Australian spelling (noun)
the position of a crank when it is in line with the connecting rod and not exerting torque	English orthography used in Australia (characterized by 'analyse', 'centre', 'usable')