What's the plural form of food colouring? Here's the word you're looking for.
Answer
The noun food colouring can be countable or uncountable.
In more general, commonly used, contexts, the plural form will also be food colouring.
However, in more specific contexts, the plural form can also be food colourings e.g. in reference to various types of food colourings
or a collection of food colourings.
