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