tectonic plates
[ (tek-ton-ik) ]
The dozen or so plates that make up the surface of the Earth. Their motion is studied in the field of plate tectonics.
notes for tectonic plates
The plates are not the same as the
continents. The North American plate, for example, extends from the middle of the
Atlantic Ocean to the west coast of the United States and
Canada. These plates are about thirty miles thick.