A thin, flat sheet of metal or other material, especially one used as an electrode in a storage battery or capacitor, or as the anode of an electron tube.
In plate tectonics, one of the sections of the Earth's lithosphere (crust and upper mantle) that is in constant motion along with other sections. It is the interaction of the plates that causes mountains, volcanos, and other land features to form and that causes earthquakes to occur. Six major plates and numerous smaller ones are recognized. See more at tectonic boundary.