water-colour vs Australian spelling

water-colour and Australian spelling both are nouns.

Word	Noun	Adjective	Verb	Adverb
water-colour	Yes	No	No	No
Australian spelling	Yes	No	No	No

water-colour (noun)	Australian spelling (noun)
the art or technique of painting with watercolors	English orthography used in Australia (characterized by 'analyse', 'centre', 'usable')
a painting produced with watercolors
a water-base paint (with water-soluble pigments); used by artists
water-soluble pigment