Wiktionary
food colouring
alt. Any substance added to food in order to change its colour. n. Any substance added to food in order to change its colour.
WordNet
food colouring
n. a digestible substance used to give color to food; "food color made from vegetable dyes" [syn: coloring, colouring, food coloring, food color, food colour]
Usage examples of "food colouring".
The machine disgorged its contents: ice, sugar and carcinogenic food colouring.
Using an oiled palette knife add the green food colouring to one half (this is a good time not to add any arsenic), turning it well to distribute the colour evenly.
Gave him a shot of good old saline solution with a bit of food colouring.
They grow it long and thick and dye it with food colouring and herbs into bright colours quite unsuitable for a person's head.