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