food colour vs food color

food colour and food color both are nouns.

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

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

food colour and food color: a digestible substance used to give color to food

Other synonyms of food colour include coloring, colouring, food coloring, food colouring.

food colour (noun)	food color (noun)
a digestible substance used to give color to food	a digestible substance used to give color to food