Main Entry:

plate tectonics

Function:

noun plural but singular in construction

Date:

1969

1: a theory in geology: the lithosphere of the earth is divided into a small number of plates which float on and travel independently over the mantle and much of the earth's seismic activity occurs at the boundaries of these plates2: the process and dynamics of tectonic plate movement ; also : a similar process on a body other than earth

— plate–tectonic adjective