Charger Plate
A large decorative base plate that sits under the dinnerware as a setting anchor.
A charger is an oversized decorative plate placed at each setting before the meal. Dishes are served on top of it, and it frames the place setting and adds color or texture to the tablescape.
Chargers are usually removed after the appetizer. They are a rental line item, so factor them into your decor rentals budget if you want that layered, finished table look.