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