Exo Planets and Planets difference?
Not all planets are exoplanets, but all exoplanets are planets.

When we differentiate the two, we use "planets" to refer to the eight planets revolving around our Sun. The Greek prefix "exo" (outside) should indicate that exoplanets orbit other stars.

In reality, you can call exoplanets "planets", and you'll often hear "Astronomers have found x planets around star y". The word "exoplanet" is used interchangeably with planets from other planetary systems.