Meaning of plate tectonics

plate' tecton'ics

Pronunciation: [key]
— Geol. Geol.
  1. a theory of global tectonics in which the lithosphere is divided into a number of crustal plates, each of which moves on the plastic asthenosphere more or less independently to collide with, slide under, or move past adjacent plates.
Random House Unabridged Dictionary, Copyright © 1997, by Random House, Inc., on Infoplease.