What is the definition of plate?

=== === A tectonic plate is a large independently moving slab of solid rock, composed of the crust and uppermost mantle (together known as the lithosphere), which floats over the layer of the earth known as the asthenosphere. A plate can be oceanic or continental and collisions and movements between and among them are ongoing as long as our planet has a highly heated interior. A plate is a circular object made from glass, plastic, paper, or ceramic. It is used to eat food or snacks off of. Plates can also refer to landforms that are created underground.