ETYM Old Fren. plate a plate of metal, a cuirsas, French plat a plate, a shallow vessel of silver, other metal, or earth, from plat flat, Greek plax. Related to Place.
(Homonym: plait).
1. A flat sheet of metal or glass on which a photographic image can be recorded; SYN. photographic plate.
2. A full-page illustration (usually on slick paper).
3. A horizontal beam that provides bearing and anchorage.
4. A main course served on a plate.
5. A metal sheathing of uniform thickness (such as the shield attached to an artillery piece to protect the gunners); SYN. scale, shell.
6. A rigid layer of the lithosphere that is believed to drift slowly.
7. A shallow receptacle for collection in church; SYN. collection plate.
8. A sheet of metal or wood or glass or plastic.
9. Any flat platelike body structure or part.
10. On which food is served or from which food is eaten.
11. The quantity contained in a plate; SYN. plateful.
12. The thin under portion of the forequarter.
According to plate tectonics, one of a number of slabs of solid rock, about a hundred kilometers thick and often several thousands of kilometers across, making up the Earth's surface.
Together, the plates make up the lithosphere.
Plates are made up of two types of crustal material: oceanic crust (sima) and continental crust (sial), both of which are underlain by a solid layer of the mantle. Oceanic crust is heavy and consists largely of basalt. It is formed at constructive margins. Continental crust is less dense and is rich in granite. It is made up of volcanic islands and folded sediments, and is usually associated with destructive margins.