chromatic color vs chromatic colour

chromatic color and chromatic colour both are nouns.

Word	Noun	Adjective	Verb	Adverb
chromatic color	Yes	No	No	No
chromatic colour	Yes	No	No	No

As nouns, chromatic color and chromatic colour are synonyms defined as:

Other synonyms of chromatic color include spectral color, spectral colour.

chromatic color (noun)	chromatic colour (noun)
a color that has hue	a color that has hue