weightplate
nounUK /ˈweɪt.pleɪt/
US /ˈweɪt.pleɪt/
A heavy flat piece of metal that you put on a bar to make it heavier when you lift.
He added another weightplate to each side of the barbell.
OTHER MEANINGS
2. A flat plate used to add mass or pressure in a machine or scale.
The old scale balanced using a small weightplate on the arm.
3. A metal disc used as ballast to steady a structure or vehicle.
The engineer bolted a weightplate to the base of the sign.
4. A flat piece of heavy material used in testing or calibration.
The technician placed a weightplate on the sensor to check its reading.