Australian spelling vs systematic desensitisation

Australian spelling and systematic desensitisation both are nouns.

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

Australian spelling (noun)	systematic desensitisation (noun)
English orthography used in Australia (characterized by 'analyse', 'centre', 'usable')	a technique used in behavior therapy to treat phobias and other behavior problems involving anxiety; client is exposed to the threatening situation under relaxed conditions until the anxiety reaction is extinguished