plate tectonic theory vs plate tectonics

plate tectonic theory and plate tectonics both are nouns.

Word	Noun	Adjective	Verb	Adverb
plate tectonic theory	Yes	No	No	No
plate tectonics	Yes	No	No	No

As nouns, plate tectonic theory and plate tectonics are synonyms defined as:

plate tectonic theory and plate tectonics: the branch of geology studying the folding and faulting of the earth's crust

Other synonyms of plate tectonic theory include tectonics.

plate tectonic theory (noun)	plate tectonics (noun)
the branch of geology studying the folding and faulting of the earth's crust	the branch of geology studying the folding and faulting of the earth's crust