Assistants in theatre? They may be Welsh (8)
I believe the answer is:
dressers
'assistants' is the definition.
(dresser is a kind of assistant)
I cannot understand how the rest of the clue works.
Can you help me to learn more?
(Other definitions for dressers that I've seen before include "Wardrobe assistants" , "Furniture" , "They are found in theatres and in kitchens" , "ones employed backstage" , "theatre assistants" .)