Pizzeria fixture (4)
I believe the answer is:
'pizzeria fixture' is the definition.
(I've seen this in another clue)
This is all the clue.
(Other definitions for oven that I've seen before include "Cooking device" , "Compartment for baking" , "You can cook in this" , "Stove" , "It''s used for baking or roasting" .)