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