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