colour television system vs color television system

colour television system and color television system both are nouns.

Word	Noun	Adjective	Verb	Adverb
colour television system	Yes	No	No	No
color television system	Yes	No	No	No

As nouns, colour television system and color television system are synonyms defined as:

colour television system and color television system: a television that transmits images in color

Other synonyms of colour television system include color television, color TV, colour television, colour TV.

colour television system (noun)	color television system (noun)
a television that transmits images in color	a television that transmits images in color