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