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