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