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