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