Question

Sentence using tectonic

Answer 1

The crust of the Earth is made of tectonic plates.

Answer 2

Tectonic is a word that refers to the structuring of the crust of planet Earth.  To use it, the sentence using this word would need to be about this particular topic.  It's often used to refer to plates that move around the surface of the planet.

To use it in a sentence, an example would be:
The scientist had chosen to study the movement of Earth's tectonic plates for his research.