baseplate
nounUK /ˈbeɪspleɪt/
US /ˈbeɪspleɪt/
A baseplate is a flat piece that goes under something to hold it up.
He put the toy house on a green baseplate so it would not fall over.
OTHER MEANINGS
2. A flat metal or plastic plate that a machine or device is attached to.
The motor is bolted to a steel baseplate.
3. In LEGO building, a flat plate with studs used as a floor for a model.
She built her castle on a large gray baseplate.
4. A removable plate on a camera or tripod that lets you attach and detach the camera quickly.
Slide the camera onto the tripod's baseplate until it clicks.
5. A flat plate at the bottom of a column or structure that spreads the load.
The workers set the column on a concrete baseplate.